Zero valent metal composite, manufacturing, system and method using thereof, for catalytically treating contaminated water

ABSTRACT

Zero valent metal composite, manufacturing thereof, using thereof, and system including thereof, for (in-situ or ex-situ) catalytically treating contaminated water, such as sub-surface water, surface water, above-surface water, water vapor, or/and gaseous water. Composite includes powdered diatomite matrix incorporated with nanometer (1-1000 nm) sized particles of a zero valent (transition) metal (iron, cobalt, nickel, copper, zinc, palladium, platinum, or/and gold) and at least one electron transfer mediator (catalyst) from porphyrinogenic organometallic complexes (e.g., metalloporphyrins (chlorophylls, hemes, cytochromes) or metallocorrins (e.g., vitamin B 12 ), and optionally, includes vermiculite. System includes composite and in-situ or/and ex-situ unit containing the composite, enabling exposure of contaminated water thereto. Applicable to in-situ sub-surface permeable reactive barriers (PRBs). Treatable water contaminants are organics (halogenated organic compounds), or/and inorganics (metal elements, metal element containing inorganic species, nonmetal elements, and nonmetal element containing inorganic species). Applicable to non-aqueous fluids (liquids, vapors, gases), for removing contaminants therefrom.

RELATED APPLICATIONS

This Application is a National Phase of PCT Patent Application No.PCT/IL2006/000010 having International Filing Date of Jan. 3, 2006,which claims the benefit of U.S. Provisional Patent Application No.60/640,214 filed on Jan. 3, 2005. The contents of the above Applicationsare all incorporated herein by reference.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a zero valent metal composite, a methodfor manufacturing thereof, a method using thereof, a system includingthereof, and an article-of-manufacture including thereof. The zerovalent metal composite is used for (in-situ or ex-situ) catalyticallytreating contaminated water. The present invention is generallyapplicable to (in-situ or ex-situ) catalytically treating any of a widevariety of different forms of contaminated water, for example,sub-surface water, surface water, above-surface water, water vapor,gaseous water, or any combination thereof, which are contaminated withany number of a wide variety of different types or kinds of organicor/and inorganic chemical contaminants. The present invention isparticularly applicable to (in-situ or ex-situ) catalytically treatingsuch forms of contaminated water wherein the water contaminants areorganic species, for example, halogenated organic compounds and halogencontaining degradation products thereof; inorganic species, for example,metal elements, metal element containing inorganic species, nonmetalelements, and nonmetal element containing inorganic species; or anycombination thereof. The present invention is also applicable to(in-situ or ex-situ) catalytically treating contaminated non-aqueousfluids (in liquid, vapor, or/and gaseous forms), for decreasingcontaminant concentrations therefrom.

Herein, in the context of the field and art of the present invention, itis to be fully understood that the terms ‘contaminated’ and ‘polluted’are synonymous and equivalent to each other, and for consistency, theterm ‘contaminated’ is generally used. Accordingly, the phrases‘contaminated water’ and ‘polluted water’ are synonymous and equivalentto each other, and, for consistency, the term ‘contaminated water’ isgenerally used. Additionally, herein, it is to be fully understood thatthe terms ‘contaminant(s)’ and ‘pollutant(s)’ are synonymous andequivalent to each other, and, for consistency, the term‘contaminant(s)’ is generally used.

Contaminated Water, and Forms Thereof:

In general, in the context of the field and art of the presentinvention, contaminated water can be any of a variety of numerousdifferent forms. Exemplary general forms of contaminated water, whichare particularly relevant to the field and art of the present invention,are sub-surface water, surface water, above-surface water, water vapor,gaseous water, and combinations thereof, which contain chemicalcontaminants.

Sub-surface water is to be understood as generally being water which is‘entirely’ located below or beneath the ground or earth. Exemplaryspecific forms of sub-surface water, which are particularly relevant tothe field and art of the present invention, are, typically naturallyexisting, but possibly human made or/and formed, ground water (i.e.,water found underground beneath the earth's surface within partially orfully saturated soil or/and porous rock), water of an aquifer (i.e., awater-bearing rock or rock formation, or an underground layer of porousrock, sand, etc., containing water), wells or springs (i.e., flows ofwater from the ground or earth), rivers, streams, lakes, ponds, pools,or sub-surface water reservoirs, which are entirely located below orbeneath the ground or earth. Additional exemplary specific forms ofsub-surface water, which are also relevant to the field and art of thepresent invention, are water that is, or/and may be, present orcontained in human made (commercial size) large volume water receiver,collection, or/and storage, vessels, containers, reservoirs, orchambers, which are entirely located below or beneath the ground orearth.

Surface water is to be understood as generally being water whose top oruppermost surface is located at about ground or earth level. Typically,but not necessarily, the top or uppermost surface of surface water isexposed to air or the atmosphere under the sky (i.e., not beneath orbelow the ground). Exemplary specific forms of surface water, which areparticularly relevant to the field and art of the present invention,are, typically naturally existing, but possibly human made or/andformed, rivers, streams, lakes, ponds, pools, surface water reservoirs,or, wells or springs, each of whose top or uppermost surface is locatedat about ground or earth level. Additional exemplary specific forms ofsurface water, which are also relevant to the field and art of thepresent invention, are water that is, or/and may be, present orcontained in human made (commercial size) large volume water receiver,collection, or/and storage, vessels, containers, reservoirs, orchambers, which are located at about ground or earth level.

Above-surface water is to be understood as generally being water whosetop or uppermost surface is located above ground or earth level.Exemplary specific forms of above-surface water, which are particularlyrelevant to the field and art of the present invention, are, typicallyhuman made or/and formed, but possibly naturally existing, above-surfacewater reservoirs, or, above-surface sources or supplies of residentialor commercial drinking, each of whose top or uppermost surface islocated above ground level. Additional exemplary specific forms ofabove-surface water, which are also relevant to the field and art of thepresent invention, are water that is, or/and may be, present orcontained in human made (commercial size) large volume water receiver,collection, or/and storage, vessels, containers, reservoirs, orchambers, which are located above ground or earth level.

Water vapor is to be understood as generally being water existing as avapor, i.e., as a barely visible or cloudy diffused form of water, suchas water mist, water fumes, or steam, suspended in air. Gaseous water isto be understood as generally being water existing in the gas phase.Such water vapor or/and gaseous water exists as either a pure vaporor/and gas of water, or as part of a vapor or/and gas mixture which alsoincludes other vapor or/and gaseous species.

In a non-limiting manner, in the context of the field and art of thepresent invention, it is to be understood that the contaminated watercan be of a form corresponding to a combination of any two or more ofthe above stated exemplary general forms, of water, i.e., sub-surfacewater, surface water, above-surface water, water vapor, and gaseouswater, and exemplary specific forms thereof, which contain chemicalcontaminants.

In general, in the context of the field and art of the presentinvention, any of the preceding described forms of contaminated water,in addition to the undesirable chemical contaminants, may contain,typically naturally existing, but possibly human made or/and formed,ground or earth types or kinds of geological matter. Exemplary specificground or earth types or kinds of geological matter, which areparticularly relevant to the field and art of the present invention, aresoil, sand, rocks, stones, pebbles (i.e., small rocks or stones),sediment (i.e., matter deposited by water or wind), fragments thereof,or any combination thereof (e.g., gravel, being an unconsolidatedcombination (mixture) of rock fragments or pebbles).

Such ground or earth types or kinds of geological matter are typicallypresent in the immediate environment or ecosystem surrounding orencompassing sub-surface and surface forms of water. In fact, bydefinition, each of the various different forms of sub-surface water,for example, ground water (i.e., water found underground beneath theearth's surface within partially or fully saturated soil or/and porousrock), water of an aquifer (i.e., a water-bearing rock or rockformation, or an underground layer of porous rock, sand, etc.,containing water), wells or springs (i.e., flows of water from theground or earth), rivers, streams, lakes, ponds, pools, or sub-surfacewater reservoirs, which are entirely located below or beneath the groundor earth, are surrounded or encompassed by immediate environments orecosystems within which are present the above stated ground or earthtypes or kinds of geological matter.

Similarly, by definition, each of the various different forms of surfacewater, for example, rivers, streams, lakes, ponds, pools, surface waterreservoirs, or, wells or springs, each of whose top or uppermost surfaceis located at about ground or earth level, are surrounded or encompassedby immediate environments or ecosystems within which are present theabove stated ground or earth types or kinds of geological matter.

Types or Kinds of Water Contaminants:

In the context of the field and art of the present invention, a watercontaminant is to be understood as generally being a chemical specie(atom, ion, radical, molecule) that is proven or known, or suspected, asbeing hazardous (poisonous or toxic), or potentially hazardous, to ahuman or animal subject. Accordingly, in the context of the field andart of the present invention, the phrase ‘contaminated water’ is to beunderstood as generally being water which contains or includes at leastone chemical specie (atom, ion, radical, molecule) that is/are proven orknown, or suspected, as being hazardous (poisonous or toxic), orpotentially hazardous, to a human or animal subject.

In general, in the context of the field and art of the presentinvention, any of the above described forms of contaminated water maycontain any number of a wide variety of different types or kinds, andforms, of contaminants. In general, water contaminants can becharacterized as being composed of organic (carbon containing) species(atoms, ions, radicals, molecules), inorganic species (atoms, ions,radicals, molecules), or any combination thereof.

In a non-limiting manner, exemplary specific types or kinds of watercontaminants composed of organic species, which are particularlyrelevant to the field and art of the present invention, are aromaticorganic compounds (i.e., aromatic hydrocarbons, or arenes), andnon-aromatic organic compounds (i.e., non-aromatic hydrocarbons,aliphatic hydrocarbons (alkanes), or conjugated hydrocarbons (alkenes,alkynes). An aromatic organic compound (aromatic hydrocarbon, or arene)type or kind of water contaminant may contain at least one halogen atom(i.e., fluorine [F], chlorine [Cl], bromine [Br], or/and iodine [I].Similarly, a non-aromatic organic compound (non-aromatic hydrocarbon,aliphatic hydrocarbon, or conjugated hydrocarbon) type or kind of watercontaminant may contain at least one halogen atom (i.e., fluorine [F],chlorine [Cl], bromine [Br], or/and iodine [I]. Accordingly, any suchhalogen containing aromatic organic compound or halogen containingnon-aromatic organic compound may be mono-halogenated orpoly-halogenated. Such halogen containing aromatic organic compounds andhalogen containing non-aromatic organic compounds are generally referredto as halogen containing organic compounds, or, synonymously andequivalently, as halogenated organic compounds. Moreover, an aromaticorganic compound or non-aromatic organic compound type or kind of watercontaminant may contain at least one heteroatom (e.g., nitrogen [N],oxygen [O], sulfur [S], or/and phosphorous [P].

In a non-limiting manner, exemplary specific types or kinds ofhalogenated organic compound water contaminants which are especiallyrelevant to the field and art of the present invention, are methylenechloride, chloroform, carbon tetrachloride, trichloroethane, di-, tri-,and tetra-chloroethylenes, polychlorinated biphenyls,tribromoneopentlyalcohol (TBNPA), and halogen containing degradationproducts thereof.

In a non-limiting manner, exemplary specific types or kinds of watercontaminants composed of inorganic species, which are particularlyrelevant to the field and art of the present invention, are metalelements, metal element containing inorganic species, nonmetal elements,and nonmetal element containing inorganic species.

Exemplary metal elements are transition metal elements, inner transitionmetal elements, and non-transition metal elements. Exemplary transitionmetal elements are zinc [Zn], cadmium [Cd], chromium [Cr], manganese[Mn], molybdenum [Mo], vanadium [V], iron [Fe], cobalt [Co], nickel[Ni], copper [Cu], silver [Ag], tungsten [W], and technetium [Tc].Exemplary inner transition metal elements are uranium [U], plutonium[Pu], cesium [Cs]. Exemplary non-transition metal elements are lead[Pb], tin [Sn], antimony [Sb], aluminum [Al], strontium [Sr], and radium[Ra]. In general, any of the above metal elements is in a neutral(elemental, or zero valent) form, or in a charged (cationic) form.Moreover, any of the above metal elements may be a radionuclide, such astechnetium-99 [Tc-99], cesium-137 [Cs-137], strontium-90 [Sr-90], andradium-226 [Ra-226].

Exemplary nonmetal elements are arsenic [As], and selenium [Se]. Ingeneral, the nonmetal element is in a neutral (elemental, or zerovalent) form, or in a charged (cationic) form.

Exemplary nonmetal element containing inorganic species are oxygencontaining inorganic species. Exemplary oxygen containing inorganicspecies are oxygen containing ions (also known as oxyions, or asoxo-anions). Exemplary oxygen containing ions are borate ions, nitrateions, sulfate ions, phosphate ions, halogenate ions (i.e., containing ahalogen), and metal oxide ions.

On-going Problem of Water Contaminated with Halogenated OrganicCompounds:

Among the wide variety of the above described different types or kindsof water contaminants, halogenated (especially, chlorinated) organiccompounds are arguably the most common, pervasive (widespread),persistent (e.g., having half-lives ranging from days to 10,000 years),proven or potentially hazardous (poisonous or toxic), undesirablecontaminants in various forms of water, such as sub-surface water,surface water, above-surface water, water vapor, gaseous water, andcombinations thereof, which contain contaminants. Many such forms ofwater are, or/and come in direct contact with, or/and lead to, sourcesof drinking water. Currently, numerous halogenated (especially,chlorinated) organic compounds are still being applied in largequantities on large scales, in a wide variety of different agriculturaland other industrial processes, by exploiting their high performance, inaddition to their relatively high stability and resistance to chemicaland biological degradation. It is now recognized that these properties,which are essential to agriculture and other industries, havedevastating effects on the environment, translating to undesirable shortand long term health problems.

The fate of anthropogenic (human originating or synthesized) halogenatedorganic compound contaminants in the environment is of great concernbecause of their proven or potential proven or potentially hazardous(poisonous or toxic) properties and characteristics. Discharge of thesecompounds into sub-surface, surface, or/and above-surface, watercontaining environments has led to extensive water contamination.Largely based on the fact that sub-surface water (for example, groundwater, water of an aquifer, wells or springs, rivers, streams, lakes,ponds, pools, or sub-surface water reservoirs, which are entirelylocated below or beneath the ground or earth) account for about 95% ofthe earth's usable fresh water resources, sub-surface watercontamination is particularly a critical issue. Intensive efforts arecontinuously being invested in the development of improved and newtechnologies for treating or remediating sub-surface water, surfacewater, or/and above-surface water, contaminated with halogenated organiccompounds.

Carbon tetrachloride (CT) is an exemplary widespread water contaminant,used mostly in the production of refrigeration fluids and propellants,and has the potential to cause cancer after long-term exposure to amaximum contaminant level (MCL), corresponding to a maximum allowableconcentration, established by the Safe Drinking Act as being safe forhuman health and the environment, of 5 ppb. From 1987 to 1993, accordingto the Toxic Release Inventory of the US Environmental Protection Agency(US EPA), releases of CT to the environment totaled nearly 76,000pounds. Perchloroethylene, in particular, tetrachloroethylene (PCE) andtrichloroethylene (TCE) are solvents widely used for dry cleaning andmetal degreasing, and can be found in household products. Their maximumcontaminant level (MCL) is 5 ppb. Both PCE and TCE were found to havetoxic effects on humans and are considered as potential carcinogenicsubstances. According to the US EPA Toxic Chemical Release Inventory,releases of PCE and TCE to land and water from 1987 to 1993 totaled over1 million pounds, and about 300,000 pounds, respectively. PCE and TCEare present in at least 771 of 852 National Priority List sitesidentified by the US EPA. It has been shown [1] that 130 liters (about0.6 drum) of the organic contaminants trichloroethane (TCA),1,1-dichloroethylene (1,1 D CE), and Freon 113, were sufficient topollute 5,000,000,000 liters of water in San Jose, Calif. Similarly, arelease of 1500 liters (about 7 drums) of TCE, PCE, and detergents,contaminated 40,000,000,000 liters of water in Cape Cod, Mass.

In spite of proven and potential environmental and health hazards, manyhalogenated compounds, among the wide variety of different types ofpersistent water contaminants, currently remain in widespreadinternational use, thereby perpetuating a continuously on-going problem.The main concern lies in the large quantities of persistentcontaminants, and their degradation products, present in, or in closeproximity to, forms of water which either are, or lead to, sources ofwater to which humans or/and animals are directly or indirectly exposed.

Current Techniques, and Limitations Thereof, for Treating or RemediatingContaminated Water:

Although not a technique per se for treating or remediating the abovestated forms of contaminated water, the concept or principle of ‘naturalattenuation’ is currently practiced for attempting to achieve oraccomplish such treatment or remediation. ‘Natural attenuation’ (NA)generally refers to the natural occurrence or taking place of any numberof various different physical, chemical, or/and biological types ofnatural phenomena, mechanisms, and processes, for example, involvingdegradation, transformation, conversion, sorption, among others, whichunder favorable conditions cause or lead to ‘natural’ reduction orattenuation of various quantifiable parameters or properties, such asmass, toxicity, mobility, volume, or/and concentration, of contaminantsin contaminated water.

A main limitation of practicing natural attenuation (NA) is based on thefact that it essentially entirely depends upon ‘naturally’ reducing orattenuating the various quantifiable parameters or properties, such asmass, toxicity, mobility, volume, or/and concentration, of the watercontaminants in the contaminated water. Meaningful natural attenuationcan require time periods of on the order of years, thus accounting forthe relatively long persistence of water contaminants in contaminatedwater.

In particular cases where the contaminated water is a form ofsub-surface water, for example, ground water, water of an aquifer, wellor spring, pond, pool, or sub-surface water reservoir, which is entirelylocated below or beneath the ground or earth, then, by practicingnatural attenuation, long time periods of continuous underground waterflow are often required for the various quantifiable parameters orproperties of the water contaminants, and possible degradation products,to be sufficiently decreased or attenuated in the underground water. Incontrast to river water, which has a turnover time on the order of twoweeks, such forms of sub-surface water have residence times on the orderof about 2 weeks to about 10,000 years. Additionally, the largehorizontally or/and vertically extending, and heterogeneous, contaminantzones or regions (contaminant plumes) of underground water types ofwater contaminants tend to be very difficult to locate, detect,characterize, and treat or remediate.

Aside from the continued practice of ‘natural attenuation’, there existsa plethora of numerous different types of well known and used prior arttechniques (methods, materials, compositions, devices, and systems) fortreating or remediating contaminated water, where the contaminated wateris a form of sub-surface water, surface water, above-surface water,water vapor, gaseous water, or any combination thereof. Each particulartechnique is primarily based on principles, phenomena, mechanisms, andprocesses, in one of the following main categories: (a)physical/physical chemical, (b) biological, or (c) chemical. A commonultimate objective of each water treatment or remediation technique isto in-situ or/and ex-situ eliminate, or at least decrease,concentrations of the hazardous (poisonous or toxic) or potentiallyhazardous water contaminants, and desirably, also, any of theirdegradation products, in the contaminated water.

The scope of the present invention encompasses treating contaminatedwater, wherein the contaminated water is, for example, a form ofsub-surface water, surface water, above-surface water, water vapor,gaseous water, or any combination thereof. For the purpose of providingexemplary background, following are brief descriptions of the abovecategorized techniques, along with selected examples of prior artteachings thereof, for treating or remediating contaminated water.

(a) Physical/Physical Chemical Techniques for Treating or RemediatingContaminated Water:

Physical/physical chemical techniques for treating or remediatingcontaminated water are based on exploiting physical or physicochemicaltypes of phenomena, mechanisms, and processes. Exemplary prior artphysical/physical chemical techniques for treating or remediatingcontaminated water are: air stripping, and air sparging, whereby aforced flow of air is used for moving or transporting, and removing,water contaminants from contaminated water; filtration, whereby a filtermedium or substrate is used for absorbing, adsorbing, and removing,water contaminants from contaminated water; and chemical destruction(without chemical reagents), whereby extreme conditions of temperatureor/and pressure are used for breaking chemical bonds of watercontaminants in contaminated water. In each technique, watercontaminants are ‘physically’ or ‘physicochemically’ moved ortransported, and removed, from contaminated water to another medium,such as air, or a filter, or are degraded, transformed, or/andconverted, in the contaminated water to non-hazardous or/and lesshazardous species.

Air stripping, as an exemplary physical/physical chemical technique fortreating or remediating contaminated water, is based on physicallytransferring volatile water contaminants from contaminated water intoair. Air stripping is considered a ‘pump and treat’ type of technique.Contaminated water is pumped into a tank containing packing material.The contaminated water trickles down through spaces between the packingmaterial towards the bottom of the tank, while at the same time a fanoperating at the bottom of the tank blows and forces air upward. Forcedair upwardly passing through the contaminated water and between thepacking material causes volatile water contaminants to evaporate outfrom the top of the tank, thereby removing the water contaminants fromthe contaminated water.

Air sparging, as another exemplary physical/physical chemical techniquefor treating or remediating contaminated water, is based on injectingair directly into contaminated water. Injected air passing through thecontaminated water physically contacts and removes water contaminantsfrom the contaminated water. The water contaminants become partitionedbetween the contaminated water and the passing air, according to Henry'slaw, and are subsequently moved or transported, and removed, from thecontaminated water to another zone or region. For example, in the caseof ground water, to a zone or region of soil unsaturated withcontaminated water. As the water contaminants are driven or diffused tothe unsaturated zone or region, a soil vapor extraction system isusually used to remove water contaminant vapors. The addition of oxygento contaminated ground water and soils also enhances biodegradation, asthe oxygen acts as a nutrient for bacteria.

Filtration, as another exemplary physical/physical chemical techniquefor treating or remediating contaminated water, is based on activatedcarbon filtration. Typically, a carbon filter is used for thistechnique. A typical activated carbon filter is made of tiny clusters ofcarbon atoms, in the bulk form of granular or powder sized particlesderived from any number of various sources, creating a highly porous andactive material with an extremely high surface area for contaminantadsorption. The contaminated water is exposed to the activated carbonfilter, during which the water contaminants diffuse and are adsorbed by,and become concentrated on, the activated carbon, and are therebyremoved from the contaminated water. After significant build up of thewater contaminants on the activated carbon, the water contaminantcontaining de-activated carbon filter is removed from the contaminatedwater, and disposed of, or, flushed or otherwise treated (regenerated)to remove the water contaminants and re-activate the carbon for re-use.

Each of the above described air stripping, air sparging, and filtration,techniques has limitations for treating or remediating contaminatedwater. Air stripping and air sparging techniques are effective only forrelatively large concentrations (over 100 ppm) of volatile contaminants.Both techniques merely move or transfer water contaminants from thecontaminated water to the air, without degrading, transforming, or/andconverting, the water contaminants to non-hazardous or/and lesshazardous environmentally acceptable species. Similarly, a significantlimitation of the filtration technique is that water contaminants areessentially only transferred from the contaminated water to the filtermedium or substrate, without being degraded, transformed, or converted,to non-hazardous or/and less hazardous environmentally acceptablespecies. Additionally, implementation of this technique requiresresources (manpower and equipment) for removing, and disposing of, or,regenerating, the de-activated filter medium or substrate which iscontaminated with the water contaminants.

Chemical destruction (without chemical reagents), as another exemplaryphysical/physical chemical technique for treating or remediatingcontaminated water, is based on using machine generated extreme ordestructive conditions of temperature or/and pressure, in the absence ofdestructive chemical reagents, for breaking chemical bonds of the watercontaminants, for the objective of destroying the water contaminants.Destruction of the water contaminants may involve degrading,transforming, or/and converting, the water contaminants to non-hazardousor/and less hazardous species. Such a technique has been proposed [2]for degrading atrazine

(being an exemplary halogenated organic compound) under high temperature(150-200° C.) and pressure (3.0-6.0 MPa).

A first significant limitation of using the technique of chemicaldestruction (without chemical reagents) for treating or remediatingcontaminated water is that the machine generated extreme conditions(typically, high temperatures or/and pressures) are relatively difficultand expensive to apply to large (areal or/and volumetric) scale forms ofcontaminated water. A second significant limitation of this technique isthat use of the machine generated extreme conditions may be accompaniedby undesirable consequences, such as partial or complete change of theimmediate environment or ecosystem, and geological matter presenttherein, surrounding or encompassing the form of contaminated waterbeing treated. This is particularly problematic if the form ofcontaminated water is surrounded or encompassed by a naturally existingenvironment or ecosystem.

(b) Biological Techniques for Treating or Remediating ContaminatedWater:

Biological techniques for treating or remediating contaminated water arebased on exploiting biological (microbiological) types of phenomena,mechanisms, and processes, involving the use of biological organisms(such as microbes, microorganisms, bacteria), for ‘biologically’degrading, transforming, converting, or/and immobilizing, the watercontaminants in the contaminated water to non-hazardous or/and lesshazardous species.

It is well known that different types of biological microorganisms areeffective for treating water contaminated with halogenated organiccompounds. For example, anaerobic type microorganisms are known forbeing able to degrade, transform, or/and convert, a wide variety ofhalogenated organic compounds. Important advantages of usingmicroorganisms are that the process of dehalogenation (especially,dechlorination) occurs in-situ, and the compounds are typicallycompletely degraded, transformed, or/and converted, thereby precludingthe need for using another method for degrading intermediate degradationproducts of the halogenated organic compounds. However, a significantlimitation of using microbiological techniques for treating contaminatedwater is that, typically, they are strongly influenced, and may beinactivated, by changes in environmental conditions, such as pH,temperature, or/and nutrient supply, which take place during the watertreatment, especially during long term water treatment.

Another significant limitation of using microbiological systems fortreating water contaminated with halogenated organic compounds is thathigh contaminant concentrations can be poisonous or toxic to thecontaminant degrading bacteria. For example, it has been shown [3] thatduring dechlorination of trichloroethylene (TCE) and vinyl chloride(VC), acetylene is an abiotically formed intermediate species which caninhibit the biotic transformation, conversion, or degradation, of theinitial halogenated organic compound contaminants.

Origin and Main Processes of Sub-surface Water Contamination:

Any given prior art technique for treating or remediating contaminatedwater, in general, and contaminated sub-surface water, in particular(e.g., ground water, water of an aquifer, well or spring, pond, pool, orsub-surface water reservoir), contaminated with organic compoundcontaminants, typically has any number and types of advantages anddisadvantages, depending upon the actual properties, parameters,characteristics, types and forms, and behavior, of the watercontaminants, and of the sub-surface water. Before describing specificproblems and limitations of current techniques which are particularlyproblematic, and difficult to overcome, for treating or remediatingcontaminated sub-surface water, in addition to those already describedhereinabove, it is useful to first briefly describe the origin and mainprocesses of sub-surface water contamination.

Following exposure of the ground or earth to chemical wastes (i.e.,contaminants), particularly involving a wide variety of numerousdifferent types or kinds of industrial or commercial processes, then,eventually, occurrence of any number and types or kinds of naturalprocesses, such as formation of moisture (i.e., from the air oratmosphere), dew, rain, snow, or/and sleet, or/and, occurrence of humanor/and machine generated processes, such as watering, or/and irrigating,among others, result in wetting the ground or earth (including thechemical wastes (contaminants) thereupon). Thereafter, the water solubleand mobile chemical wastes (contaminants), and possible initialdegradation products thereof, become dissolved, transported, and, as aresult of various diffusion, adsorption, desorption, and mass transferprocesses, become heterogeneously distributed into, throughout, andamong, various different horizontally or/and vertically extending zonesor regions of the above stated types and forms of sub-surface water.

Such zones or regions of the different forms of sub-surface water beginat, and extend to, varying depths below or beneath the top or uppermostsurface layer of the ground or earth. For example, such zones or regionsof sub-surface water typically begin from a depth of about 5centimeters, and can extend to a depth of about 2000 meters, below orbeneath the top or uppermost surface layer of the ground or earth. Inthe particular case where the sub-surface water is a form of groundwater, water of an aquifer, well or spring, pond, pool, or sub-surfacewater reservoir, then, dissolution, transport, and heterogeneousdistribution, of the chemical contaminants may generate relatively largehorizontally or/and vertically extending concentrated contaminant zonesor regions, which are well known in the field and art as contaminantplumes (i.e., specific sub-surface water zones or regions concentratedwith contaminants).

Limitations and Problems Particularly Relevant to Treating orRemediating Contaminated Sub-surface Water:

In particular cases where the contaminated water is a form ofsub-surface water, for example, ground water, water of an aquifer, wellor spring, pond, pool, or sub-surface water reservoir, which is entirelylocated below or beneath the ground or earth, then, there exist severallimitations and problems particularly relevant to treating orremediating such contaminated sub-surface water. As stated hereinabove,practicing natural attenuation is often limited by requiring long timeperiods, for example, possibly up to 10,000 years, of continuousunderground water flow for the various quantifiable parameters orproperties of the water contaminants, and possible degradation products,to be sufficiently decreased or attenuated in the underground water.Additionally, large horizontally or/and vertically extending, andheterogeneous, concentrated contaminant zones or regions (contaminantplumes) of underground water types of water contaminants tend to be verydifficult to locate, detect, characterize, and treat or remediate.

Another limitation and problem particularly relevant to treating orremediating contaminated sub-surface water concerns non-aqueous phaseliquids (NAPLs), for example, trichloroethylene (TCE),tetrachloroethylene (PCE), and carbon tetrachloride (CT). During releaseto the ground or earth, followed by subsequent migration intosub-surface water, the total mass of each contaminant is distributedamong various sub-surface phases by diffusion of liquids and vapors.Additionally, various adsorption or/and desorption processes involvingthe NAPLs take place throughout sub-surface ground or earth types ofgeological matter (e.g., soil, sand, rocks, stones, pebbles, sediment,or/and gravel), which are typically present in the immediate environmentsurrounding or encompassing the contaminated sub-surface water.Dissolution of NAPLs and subsequent transport of dissolved constituentsby sub-surface water generate the above described large horizontallyor/and vertically extending, and heterogeneous, concentrated contaminantzones or regions (contaminant plumes).

A similar limitation and problem particularly relevant to treating orremediating contaminated sub-surface water concerns dense non-aqueousphase liquids (DNAPLs), which, because of their relatively high densityand low water solubility, sink through soil and water and followtopographic lows within the sub-surface water environment, displace thelower lying sub-surface water, and accumulate upon the underlying claystratum in the form of concentrated contaminant zones or regions(contaminant plumes). Further, since most DNAPLs are sparingly solublein water, they are adsorbed on to sub-surface ground or earth types ofgeological matter, particularly soil particles, producing tenaciousunderground plumes of dissolved organic contaminants which cannot bereadily and permanently removed by standard ‘pump and treat’technologies.

Such sub-surface concentrated contaminant zones or regions (contaminantplumes), and residuals thereof, eventually become primary sources ofsub-surface water contamination. Under natural conditions, the timerequired for complete dissolution or degradation of DNAPLs can behundreds of years. Not knowing the location, characteristics, and size,of DNAPL sub-surface concentrated contaminant zones or regions(contaminant plumes), make it practically impossible to predict how longa pump and treat system must operate in order to sufficiently treat orremediate the contaminated sub-surface water. Moreover, heterogeneous,such as perched, topographies of DNAPL sub-surface concentratedcontaminant zones or regions (contaminant plumes), complicatesub-surface water site investigations. It is very easy to unknowinglydrill through the concentrated contaminant zone or region (contaminantplume) and the bed it sits on, causing contaminated water in theconcentrated contaminant zone or region to drain down through thedrilled hole into a deeper part of the sub-surface water environment,or/and into a different sub-surface water zone or region and contaminatethe sub-surface water contained therein.

(c) Chemical Techniques for Treating or Remediating Water Contaminatedwith Halogenated Organic Compounds:

Chemical techniques for treating or remediating water contaminated withhalogenated organic compounds are based on exploiting non-catalyticchemical reaction, or (homogeneous or heterogeneous) catalytic chemicalreaction, types of phenomena, mechanisms, and processes, involving theuse of (inorganic or/and organic) chemical reagents, for ‘chemically’degrading, transforming, or/and converting, the halogenated organiccompound water contaminants in the contaminated water to non-hazardousor/and less hazardous species.

In a non-catalytic chemical reaction type of chemical technique, atleast one of the chemical reagents is a main reactant which directlyreacts (without a catalyst) with the halogenated organic compoundcontaminant(s) in a non-catalyzed chemical reaction, typically, a redox(reduction-oxidation) chemical reaction, for degrading, transforming,or/and converting, the halogenated organic compounds in the contaminatedwater to non-hazardous or/and less hazardous compounds. In a homogeneousor heterogeneous catalytic chemical reaction type of chemical technique,at least one of the chemical reagents is a participant, facilitator, orexpeditor, functioning as a homogeneous or heterogeneous catalyst in ahomogeneous or heterogeneous catalytic chemical reaction, typically, ahomogeneous or heterogeneous redox (reduction-oxidation) catalyticchemical reaction, involving the halogenated organic compoundcontaminant(s), for transforming, converting, or degrading, thehalogenated organic compounds in the contaminated water.

Herein, for the purpose of clearly understanding, without ambiguity, thefollowing presentation of prior art teachings, as well as of the subjectmatter of the present invention, a homogeneous catalytic chemicalreaction is wherein the catalyst (particularly, e.g., an electrontransfer mediator) is an initially solid (typically, particulate)substance that is non-supported, non-matrixed, non-intercalated, or/andnon-trapped, by another material, and subsequently becomes freely mobileand soluble throughout the contaminated water. A heterogeneous catalyticchemical reaction is wherein the catalyst (particularly, e.g., anelectron transfer mediator) is an initially solid (typically,particulate) substance that is supported, matrixed, intercalated,incorporated, or/and trapped, and generally immobile, on or/and insideof a (particulate or/and non-particulate) solid support or matrixmaterial which subsequently becomes dispersed (i.e., not dissolved)throughout the contaminated water. Ordinarily, the initially immobilizedcatalyst similarly becomes dispersed (i.e., not dissolved) throughoutthe contaminated water, but, may at least partially dissolve in thecontaminated water, depending upon actual parameters and conditions of agiven heterogeneous catalytic chemical reaction system.

Chemical Destruction (with Chemical Reagents):

Chemical destruction (with chemical reagents), as an exemplary chemicaltechnique for treating or remediating contaminated water, is based onusing ‘destructive’ chemical reagents (e.g., strong chemical oxidizers),under existing conditions of temperature or/and pressure, or,alternatively, under machine generated extreme or destructive conditionsof temperature or/and pressure, for breaking chemical bonds of the watercontaminants, for the objective of destroying the water contaminants.Destruction of the water contaminants may involve degrading,transforming, or/and converting, the water contaminants to non-hazardousor/and less hazardous species.

A first significant limitation of using the technique of chemicaldestruction (with chemical reagents) for treating or remediatingcontaminated water is that use of the destructive chemicals can bedifficult, potentially hazardous, and expensive, to apply to large(areal or/and volumetric) scale forms of contaminated water. A secondsignificant limitation of this technique is that the types or kinds ofdestructive chemicals which are required for being sufficientlyeffective in destroying the water contaminants are usually non-specific,whereby their use may be accompanied by undesirable consequences, suchas partial or complete change of the immediate environment or ecosystem,and geological matter present therein, surrounding or encompassing theform of contaminated water being treated. This is particularlyproblematic if the form of contaminated water is surrounded orencompassed by a naturally existing environment or ecosystem. Forexample, the destructive chemical reagents used for degrading,transforming, or/and converting, the water contaminants to non-hazardousor/and less hazardous species, may themselves be hazardous or/andpotentially hazardous, or/and may introduce hazardous or/and potentiallyhazardous conditions, in the immediate environment or ecosystem, andgeological matter present therein, surrounding or encompassing the formof contaminated water being treated.

Reductive Dehalogenation:

Currently, most chemical techniques used for treating or remediatingwater contaminated with halogenated organic compounds are based onreductive dehalogenation (typically, dechlorination) types ofnon-catalytic or (homogeneous or heterogeneous) catalytic, redoxchemical reactions, phenomena, mechanisms, and processes, involving theuse of (organic or/and inorganic) chemical reagents, for ‘chemically’dehalogenating (dechlorinating) the halogenated organic compounds in thecontaminated water. In general, reductive dehalogenation involvestransfer of a number of electrons (ne⁻), either in the absence orpresence of a catalyst (such as an electron transfer mediator typecatalyst), from a bulk electron donor or reducing agent (being any of awide variety and combinations of numerous possible organic or/andinorganic chemicals (for example, naturally existing in, originatingfrom, or synthetically derived from, mineral matter, plant matter, orbiological matter)), to an electron acceptor, being the halogenated(typically, chlorinated) organic compound contaminant ([R—X]; X=halogen,typically, chlorine [Cl]). The reductive dehalogenation chemicalreaction is a form of (non-catalytic or catalytic) hydrogenolysis whosegeneral scheme (without or with a catalyst) is indicated by chemicalequation (1), wherein Y⁺ is a proton [H⁺] or any other positivelycharged atom or moiety:R—X+ne ⁻+Y⁺→R—Y+X⁻  (1)

Phytochemical Reductive Dehalogenation For Treating or Remediating(Phytoremediating) Water Contaminated with Halogenated OrganicCompounds:

A first exemplary type of reductive dehalogenation for treating orremediating water contaminated with halogenated organic compounds isbased on phytochemistry (plant chemistry). Phytochemical types ofreductive dehalogenation (typically, dechlorination) non-catalytic orcatalytic redox chemical reactions, involving the use of aquatic orterrestrial plants or plant derived chemicals as the bulk electrondonors or reducing agents, for ‘phytochemically’ dehalogenating(dechlorinating) or ‘phytodegrading’ various different kinds ofhalogenated organic compounds in contaminated or polluted water, havebeen well studied [e.g., 4-8].

Zero Valent Metal (ZVM) Reductive Dehalogenation for Treating orRemediating Water Contaminated with Halogenated Organic Compounds:

A second exemplary type of reductive dehalogenation for treating orremediating water contaminated with halogenated organic compounds isbased on the use of elemental metal or a zero valent metal (ZVM). Thezero valent metal (ZVM) reductive dehalogenation (typically,dechlorination) technique is generally based on exposing watercontaminated with halogenated organic compounds to a bulk quantity ofgranular or/and powdered elemental metal particles in the metallic orzero valent state, during which the contaminants are degraded,transformed, or/and converted, to non-hazardous or/and less hazardousspecies, or/and are immobilized on the surface of the metal particles,for example, by adsorption or/and precipitation processes. Typically,exposing the contaminated water to the zero valent metal particles isperformed in a manner, for example, under reducing (anaerobic or anoxic)conditions, such that only contaminant species in the contaminatedwater, and not non-contaminant species (such as oxygen gas) in thecontaminated water or/and in the immediate vicinity of the contaminatedwater, are reduced by the zero valent metal particles.

The general mechanism of zero valent metal (ZVM) reductivedehalogenation involves a two-electron transfer which occurs eitherdirectly on the metal surface, or/and through some intermediary(catalyst), in particular, depending upon the absence or presence of acatalyst, from the bulk electron donor or reducing agent (which becomesoxidized), to the halogenated organic compound contaminant ([R—X];X=halogen, typically, chlorine [Cl]) as the electron acceptor, therebyreducing the halogenated organic compound contaminant, for example, to areduced form [R—H], as generally indicated by chemical equation (2),wherein Y⁺ is a proton [H⁺] or any other positively charged atom ormoiety:R—X+M⁰+Y⁺→M²⁺+R—Y+X⁻  (2)

Although different elemental or zero valent metals, for example, iron[Fe⁰], cobalt [Co⁰], nickel [Ni⁰], copper [Cu⁰], and zinc [Zn⁰], areapplicable, zero valent iron [Fe⁰] (ZVI) is most commonly used forimplementing the ZVM technique. The zero valent metal reductivedehalogenation process has been known for years, however, only duringthe past decade has the use of ZVM, in general, and ZVI, in particular,become accepted as one of the most effective means of sub-surface water(e.g., ground water, aquifer water) remediation. ZVI particles arerelatively inexpensive, and reasonably effective for in-situ or ex-situcatalytically reducing concentrations of a wide variety of differenttypes of water contaminants, such as organic species, for example,halogenated organic compounds and halogen containing degradationproducts thereof, and inorganic species, for example, metal elements,metal element containing inorganic species, and oxygen containinginorganic species (e.g., oxygen containing ions (oxyions, oroxo-anions), such as borate ions, nitrate ions, sulfate ions, phosphateions, halogenate ions (i.e., containing a halogen), and metal oxideions).

In particular cases where the contaminated water is a form ofsub-surface water, for example, ground water, water of an aquifer, wellor spring, pond, pool, or sub-surface water reservoir, then, in actualfield applications, the ZVM technique is typically implemented byplacing a bulk quantity of granular or/and powdered zero valent metal(ZVM) particles, alone or with other reactive or/and inactive materials,in a sub-surface permeable reactive barrier (PRB). A sub-surfacepermeable reactive barrier (PRB) is a closed or open structure orconfiguration, such as a filled in trench, wall, or well, or a system ofseveral closed or/and open structures or configurations, that providespassive interception and in-situ treatment of contaminated sub-surfacewater (e.g., ground water, aquifer water). A sub-surface permeablereactive barrier is characterized by having a permeable zone containingor creating a reactive treatment area, including a highly reactivematerial, for example, ZVM particles, and optionally, also including aless reactive, an inactive, or/and a non-reactive material, oriented tointercept and remediate or purify a sub-surface water (e.g., groundwater, aquifer water) contaminant plume (i.e., a specific sub-surfaceregion or zone concentrated with contaminants), by direct exposure ofthe water contaminants to the reactive material.

Ideally, a sub-surface permeable reactive barrier provides apreferential flow path of the contaminated sub-surface water (e.g.,ground water, aquifer water) through the reactive material, and theother possibly present materials, and degrades, transforms, or/andconverts, the water contaminants into environmentally acceptable(non-hazardous or/and less hazardous) species which exit the barrier,while minimally disrupting natural flow of the sub-surface water (e.g.,ground water, aquifer water). Typically, the contaminated sub-surfacewater (e.g., ground water, aquifer water) flows by natural flow(pressure or current) gradients through the sub-surface PRB, however,pumping schemes configured upstream, within, or/and downstream, thesub-surface PRB, can also be used for implementing a sub-surface PRBsetup. A sub-surface PRB can be installed as a permanent orsemi-permanent closed or open structure or configuration spanning alongor/and across the flow path of a sub-surface water contaminant plume.Alternatively, a sub-surface PRB can be installed as a construction orconfiguration as part of an in-situ reactor which is readily accessibleto facilitate the removal or/and replacement of the spent (deactivated)reactive zero valent metal material, and the other possibly presentmaterials.

There are extensive prior art teachings [e.g., 9-16] about the ZVMtechnique, typically involving use of zero valent iron (ZVI) innon-catalytic reaction systems, for non-catalytically reductivelydechlorinating chlorinated organic solvents, such as carbontetrachloride (CT) [C(Cl)₄], dichloroethylene (dichloroethene) (DCE)[C₂H₂Cl₂], trichloroethylene (trichloroethene) (TCE) [C₂HCl₃],perchloroethylene (PCE) (tetrachloroethylene, tetrachloroethene)[C₂Cl₄], among many others, which are of significant environmentalconcern.

Electron Transfer Mediators as Catalysts of Reductive DehalogenationReactions:

An active area in the field of environmental science and technology,focusing on treating or remediating water contaminated or polluted withhalogenated organic compounds, concerns the use of electron transfermediators for (homogeneously or heterogeneously) catalyzing reductivedehalogenation (typically, dechlorination) of halogenated organiccompounds under reducing (typically, anaerobic or anoxic) conditions.

Electron transfer mediators are chemical substances, functioning ascatalysts or co-catalysts, which are catalytically active, and expedite(catalyze) redox (reduction-oxidation) types of chemical reactions, suchas reductive dehalogenation, by participating in, mediating, andexpediting, the transfer of electrons from a bulk electron donor orreducing agent to an electron acceptor, or/and by stabilizingintermediate forms of the redox reactants. An electron transfer mediatorwhich specifically functions by participating in, mediating, andexpediting, the transfer of electrons from a bulk electron donor orreducing agent to an electron acceptor is also known as an electroncarrier or as an electron shuttle, since electrons are carried andshuttled by such a chemical species.

Based on the above described general mechanism of reductivedehalogenation, along with reference to chemical equation (1), thegeneral mechanism of an electron shuttle type of reductivedehalogenation system which includes an electron transfer mediator typecatalyst is as follows. Under reducing conditions, in the presence of anelectron transfer mediator type catalyst, the bulk electron donor orreducing agent transfers the electrons (ne⁻) to an electron transfermediator molecule, which becomes reduced, during which the bulk electrondonor or reducing agent becomes oxidized. The reduced electron transfermediator molecule then carries (shuttles) and transfers the electrons toa halogenated organic compound contaminant [R—X] electron acceptor,which becomes reduced [R—Y], during which the electron transfer mediatormolecule becomes oxidized. The oxidized electron transfer mediatormolecule is then reduced again by the bulk electron donor or reducingagent, thus enabling the electron transfer mediated catalytic reductivedehalogenation cycle to repeat.

Numerous laboratory studies [e.g., 17-22] have shown that reductivedegradation, transformation, or/and conversion, of certain relativelyoxidized organic compounds (such as halogenated organic compounds) canbe expedited (i.e., catalyzed) by use of electron transfer mediator typecatalysts in electron shuttle systems.

In general, electron shuttle systems involve the use of naturallyoccurring organic macrocycles complexed with transition metals, aselectron transfer mediators, to carry and shuttle electrons from thebulk electron donor or reducing agent to the electron acceptor, therebyreductively degrading, transforming, or/and converting, the electronacceptor (halogenated organic compound). These relatively simplelaboratory abiotic (but biomimetic) systems typically exhibit fasterreaction rates relative to systems utilizing direct biological reductionreactions. Several naturally occurring biogeochemical substances, suchas mineral substances, naturally occurring organic matter (NOM),bacterial transition metal coenzymes, and other biomimetic macrocycles,have been proposed and studied for use as electron transfer mediatortype catalysts [e.g., 17, 20; 23-29].

Prior art also includes various teachings of such electron transfermediated catalytic reductive dehalogenation reaction systems, where theelectron transfer mediator type catalyst is a humic substance [e.g.,30-32]; a quinone [e.g., 33]; or a protein [e.g., 28].

Porphyrinogenic Organometallic Complexes (Electron Transfer MediatorCatalytic Functionality):

The term ‘porphyrinogenic organometallic complex’ refers to anorganometallic complex formed between a neutral metal atom or a metalion and a porphyrinogenic or porphyrinogenic-like ring system, and isfurther defined and exemplified hereinbelow in the Description of thepresent invention.

Metalloporphyrin complexes (commonly known and referred to asmetalloporphyrins), being porphyrinogenic organometallic complexes ofmetal ions and porphyrin ligands, are organic tetrapyrrole macrocyclescomposed of four pyrrole type rings joined by methane (methylidene)bridges and complexed to a central metal ion. They form a near planarstructure of aromatic macrocycles containing up to 22 conjugated πelectrons, 18 of which are incorporated into the delocalization pathwayin accordance with Huckel's [4n+2] rule of aromaticity. One or two ofthe peripheral double bonds of the porphyrin ligands of ametalloporphyrin can undergo an addition reaction to form ametalloporphyrin derivative, such as a metallocorrin or a metallochlorintype of porphyrinogenic organometallic complex.

There are extensive teachings [e.g., 34] about the origin, and thenumerous physical, chemical, and biological, properties,characteristics, and behavior, of porphyrinogenic organometalliccomplexes, of which thousands have been identified and studied [e.g.,35, 36]. Exemplary well known metalloporphyrin complexes arechlorophylls, which are magnesium (II) complexes; hemes, which are iron(II) complexes; and cytochromes (e.g., cytochrome P450, and cytochromeP430) Vitamin B₁₂ (cyanocobalamin) a naturally occurring, orsynthesized, metalloporphyrin-like complex of related structure andfunction, is a metallocorrin type of porphyrinogenic organometalliccomplex composed of a corrin ligand (a porphyrin analog in which some ofthe methylene bridges are substituted or/and absent) complexed to acobalt (III) ion.

Porphyrinogenic organometallic complexes, such as metalloporphyrins,metalloporphyrin-like complexes, and their derivatives, exist in manybiochemical environments, such as living cells, soils, sediments,bitumens, coal, oil shales, petroleum, and other types of naturallyoccurring deposits rich in organic matter [e.g., 37-39]. Porphyrinogenicorganometallic complexes are well known for functioning as electrontransfer mediators, and play an important role in various biochemicalpathways, such as oxygen transport and storage (hemoglobin andmyoglobin, respectively) and electron transfer in redox(reduction-oxidation) reactions (cytochromes).

Porphyrinogenic organometallic complexes exhibit several particularproperties, characteristics, and behavior, which make them especiallywell applicable for functioning as electron transfer mediator typecatalysts in homogeneous or heterogeneous electron transfer mediatedcatalytic reductive dehalogenation (typically, dechlorination) reactionsystems, for catalyzing reductive dehalogenation of halogenated organiccompound contaminants in water under reducing (anaerobic or anoxic)conditions. Porphyrinogenic organometallic complexes are: (1) effectiveredox catalysts for many reactions, and have a long range of redoxactivity; (2) electrochemically active with almost any core metal; (3)active catalysts in aqueous solution under conditions particularlypertinent to environments of various different forms of contaminatedsub-surface water and surface water; and (4) relatively highly stable,thereby enabling reactions to take place under severe conditions, whereother types of reactions probably would not take place.

Porphyrinogenic organometallic complexes, such as metalloporphyrins andmetalloporphyrin-like complexes, are well known for being used aselectron transfer mediator type catalysts in homogeneous catalyticreduction processes. There are numerous prior art teachings [e.g.,17-22; 40-51] about electron transfer mediated homogeneous catalyticreductive dehalogenation (typically, dechlorination) reaction systems,involving the use of various different porphyrinogenic organometalliccomplexes as homogeneous electron transfer mediator type catalysts(i.e., an initially solid (typically, particulate) substance that isnon-supported, non-matrixed, non-intercalated, or/and non-trapped, byanother material, and subsequently becomes freely mobile and solublethroughout the contaminated water), for homogeneously catalyzingreductive dehalogenation of halogenated organic compounds, such ashalogenated organic solvents or other non-herbicide type halogenatedorganic compounds, particularly those which are known problematiccontaminants or pollutants in water. In the above cited prior art,halogenated (chlorinated) organic compounds most extensively andfrequently studied are: chlorinated methanes, chlorinated ethanes,chlorinated ethylenes (ethenes), chlorinated phenols (chlorophenols),and polychlorinated biphenyls (PCBs).

There are also prior art teachings [e.g., 8] of using hematin (reducedform of the porphyrin heme), or the metalloporphyrin hemoglobin, as anelectron transfer mediator type catalyst, in the presence of dithionite(hydrosulfite) [S₂O₄ ⁻²] as a bulk electron donor or reducing agent, forhomogeneous catalytic reductive dehalogenation (dechlorination) anddegradation, in aqueous solutions, of various enantiomeric forms andanalogs of the (bridged diphenyl) halogenated organic compound DDT(p,p′-DDT) (DichloroDiphenylTrichloroethane) [C₁₄H₉Cl₅], historicallywell known as an extremely hazardous water contaminant.

Electron Transfer Mediators as Catalysts in Heterogeneous Composites,for Reductive Dehalogenation:

Studies have shown that porphyrinogenic organometallic complexes, suchas metalloporphyrins, can be incorporated (via intercalation) andimmobilized on or/and in layered minerals, or amorphous silica gelsurfaces, for forming heterogeneous composites that can be used forheterogeneously catalyzing electron transfer mediated reactions. Forexample, heterogeneous composites composed of the cobaltmetalloporphyrin, tetramethylpyridilporphyrin [5, 10, 15,20-tetrakis(1-methyl-4-pyridinio)-porphine-cobalt] [TMPyP-Co],incorporated on or/and in silica gel and double-layered clays were usedfor heterogeneously catalyzing reductive dechlorination of carbontetrachloride [CCl₄] in water [52]. Prior art [e.g., 53] also includesteachings about incorporating and immobilizing metalloporphyrins onor/and in sepharose, sephadex, or polystyrene, types of solid support ormatrix materials, for forming heterogeneous composites that can be usedfor heterogeneously catalyzing electron transfer mediated reductivedechlorination reactions.

Diatomite (Diatomaceous Earth, Kieselguhr):

Diatoms (bacillariophyceae) are microscopic, about 1 to 500 μm sized,unicellular algae found in both freshwater and marine environments.These single-celled plants develop external, amorphous silica skeletons(frustules) possessing pores having sizes on the order of nanometers.These pores are uniform in diameter, with dimensions that are speciesspecific. The smallest of these pores have diameters in the range ofabout 20 to 200 nm. The structure of a diatom is similar to that of apillbox. The siliceous shell or ‘test’ is made of opaline silica(SiO₂.nH₂O). Diatoms are found in fresh, salt, or brackish, water,wherein many species are found floating in the surface layers of thewater, although the majority are benthic, ‘floor dwelling’ species.

Diatomite, also known as diatomaceous earth or kieselguhr, is a porous,chalk-like, sedimentary rock, formed by fossil accumulation of diatomsin the form of amorphous, hydrated silica. Diatomite is highlyabsorbent, physically and chemically stable, nearly indestructible, andordinarily chemically inert to most common water contaminants. Diatomiteis readily crushed or/and physically processed into a powdered form, andsieved into specific average particle size ranges according toparticular applications.

Due to the ability of diatomite to absorb its own weight in liquid, itsmajor uses are as absorbent materials and industrial filters. Diatomiteis used in a variety of food production applications, such asclarification and filtration of beer and wines, refining sugar andsweeteners, and, filtering fruit juices, oils, and syrups. Heavierindustry uses diatomite filters for filtration and stabilization ofpharmaceuticals, serums, and other pharmaceutical and biotechnologyapplications, and chemicals that include liquid acids and other liquidwastes. The porous characteristic of diatomaceous earth allowsindustries to exploit this quality and use it as an absorbent for gases,noxious materials, soluble fertilizing agents, sealing wax, pasteboard,rubber erasers, and, fatty and acidic materials. Diatomite is also usedas a filler, to ‘bulk out’ finished manufactured products, as it isordinarily non-reactive. Such products are paints, lacquers, rubbers,plastics, polishes, agricultural chemicals (agrochemicals), insulation,anti-caking agent, cement, concrete, animal feeds, and fertilizers.Diatomite is also well known and widely used as a non-reactive orminimally reactive support, substrate, carrier, matrix, or dispersingagent, material, singly, or in combination with other similar types ofmaterials, for heterogeneous catalysts, including, for example, ZVMtypes of catalysts.

Vermiculite:

Vermiculite is the mineralogical name given to any of a group ofmicaceous hydrated silicates of varying composition, related to thechlorites. Vermiculite exfoliates or expands upon heating. In theexfoliated or expanded state, vermiculite has many applications in awide variety of different types of fields and industries, such ashorticulture and agriculture. Among the many applications, vermiculiteis commonly used in the horticultural and botanical industries becauseit provides both aeration and drainage, it retains and holds substantialamounts of water and later releases it as needed, it is sterile and freefrom diseases, it has a fairly neutral pH, and it is readily available,non-toxic, safe to use, and relatively inexpensive.

Several specific horticultural and botanical applications involving theuse of vermiculite are blocking mixes, hydroponics, micro-propagation,potting mixes, rooting cuttings, seed germination, seedling wedgemix,sowing composts, and twin scaling bulbs. Several specific agriculturalapplications involving the use of vermiculite are animal feeds,anti-caking materials, bulking agents, fertilizers, pesticides, seedencapsulants, and soil conditioners. Additional industrial applicationsinvolving the use of vermiculite are absorbent packing materials,dispersions, drilling muds, filtration, fixation of hazardous materials,and nuclear waste disposal. Vermiculite is also used as a filler, to‘bulk out’ finished manufactured products, as it is ordinarilynon-reactive. Vermiculite is also known and used as a non-reactive orminimally reactive support, substrate, carrier, matrix, or dispersingagent, material, singly, or in combination with other similar types ofmaterials, for heterogeneous catalysts. Due to its chemical compositionincluding the presence of Fe⁺², vermiculite has been reported to be anactive compound in the reduction of halogenated (e.g., chlorinated)organic compounds present in contaminated water.

Although there exists a plethora of numerous different types of wellknown and used prior art techniques (methods, materials, compositions,devices, and systems) for treating or remediating contaminated water,there remains on-going need for improving current techniques, as well asfor identifying, developing, and implementing, new techniques, forexample, with respect to techniques based on the use of zero valentmetal materials, for treating or remediating contaminated water.Accordingly, new, technologically and economically feasible, andeffective treatment and remediation techniques need to be developed andimplemented in order to meet stringent water quality standards, and toreduce environmental and health risks associated with pervasive(widespread), persistent (e.g., having half-lives ranging from days to10,000 years), proven or potentially hazardous (poisonous or toxic),undesirable contaminants in various forms of water, especially suchforms of water which are, or/and come in direct contact with, or/andlead to, sources of drinking water.

There is thus a need for, and it would be highly advantageous to have azero valent metal composite, a method for manufacturing thereof, amethod using thereof, a system including thereof, and anarticle-of-manufacture including thereof, wherein the zero valent metalcomposite is used for (in-situ or ex-situ) catalytically treatingcontaminated water. Moreover, there is a need for such an inventionwhich is generally applicable to (in-situ or ex-situ) catalyticallytreating any of a wide variety of different forms of contaminated water,for example, sub-surface water, surface water, above-surface water,water vapor, gaseous water, or any combination thereof, which arecontaminated with any number of a wide variety of different types orkinds of organic or/and inorganic chemical contaminants. Furthermore,there is a need for such an invention which is particularly applicableto (in-situ or ex-situ) catalytically treating such forms ofcontaminated water wherein the water contaminants are organic species,for example, halogenated organic compounds and halogen containingdegradation products thereof; inorganic species, for example, metalelements, metal element containing inorganic species, nonmetal elements,and nonmetal element containing inorganic species; or any combinationthereof.

SUMMARY OF THE INVENTION

The present invention relates to a zero valent metal composite, a methodfor manufacturing thereof, a method using thereof, a system includingthereof, and an article-of-manufacture including thereof. The zerovalent metal composite is used for (in-situ or ex-situ) catalyticallytreating contaminated water. The present invention is generallyapplicable to (in-situ or ex-situ) catalytically treating any of a widevariety of different forms of contaminated water, for example,sub-surface water, surface water, above-surface water, water vapor,gaseous water, or any combination thereof, which are contaminated withany number of a wide variety of different types or kinds of organicor/and inorganic chemical contaminants. The present invention isparticularly applicable to (in-situ or ex-situ) catalytically treatingsuch forms of contaminated water wherein the water contaminants areorganic species, for example, halogenated organic compounds and halogencontaining degradation products thereof; inorganic species, for example,metal elements, metal element containing inorganic species, nonmetalelements, and nonmetal element containing inorganic species; or anycombination thereof. The present invention is also applicable to(in-situ or ex-situ) catalytically treating contaminated non-aqueousfluids (in liquid, vapor, or/and gaseous forms), for decreasingcontaminant concentrations therefrom.

The zero valent metal composite, of the present invention, is composedof a powdered diatomite matrix on or/and in which is incorporated zerovalent metal particles having a size in a range of between about 1 nmand about 1000 nm and at least one electron transfer mediator. In aparticular embodiment of the present invention, the zero valent metalcomposite is composed of a composition consisting essentially of apowdered diatomite matrix on or/and in which is incorporated zero valentmetal particles having a size in a range of between about 1 nm and about1000 nm and at least one electron transfer mediator.

Exemplary applicable zero valent metals are zero valent transitionmetals, for example, iron, cobalt, nickel, copper, zinc, palladium,platinum, gold, or any combination thereof.

In general, essentially any electron transfer mediator functioning as anactive redox catalyst under reducing (anaerobic or anoxic) conditionscan be used for implementing the present invention. Preferably, the atleast one electron transfer mediator is selected from the groupconsisting of a porphyrinogenic organometallic complex, an analogthereof, a derivative thereof, and any combination thereof. Forimplementing the present invention, preferably, the at least oneporphyrinogenic organometallic complex is selected from the groupconsisting of metalloporphyrin complexes, metallocorrin complexes,metallochlorin complexes, and any combination thereof.

Preferably, the metalloporphyrin complex is composed of a transitionmetal complexed to a (initially free base) porphyrin selected from thegroup consisting of:

tetramethylpyridilporphyrin[5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphine], abbreviated as[TMPyP],

tetrahydroxyphenylporphyrin[5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine], abbreviated as[TP(OH)P],

tetraphenylporphyrin [5,10,15,20-tetraphenyl-21H,23H-porphine],abbreviated as [TPP], and

meso-tetraphenylporphyrin-4,4′,4″,4′″-tetrasulfonic acid[5,10,15,20-tetrakis(benzenesulfonic acid)porphine], abbreviated as[TBSAP].

The transition metal is essentially any transition metal capable ofcomplexing with the just stated porphyrins for forming the correspondingmetalloporphyrin complex. Preferably, the transition metal is selectedfrom the group consisting of cobalt [Co], nickel [Ni], iron [Fe], zinc[Zn], and copper [Cu].

Accordingly, for implementing the present invention, preferably, themetalloporphyrin complexes are selected from the group consisting of:

tetramethylpyridilporphyrin-transitionmetal[5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphine-transitionmetal], abbreviated as [TMPyP-transition metal],

tetrahydroxyphenylporphyrin-transition metal[5,10,15,20-tetrakis(4-hydroxyphenyl)-21H, 23H-porphine-transitionmetal], abbreviated as [TP(OH)P-transition metal],

tetraphenylporphyrin-transition metal[5,10,15,20-tetraphenyl-21H,23H-porphine-transition metal], abbreviatedas [TPP-transition metal],

meso-tetraphenylporphyrin-4,4′,4″,4′″-tetrasulfonic acid-transitionmetal [5, 10, 15, 20-tetrakis (benzenesulfonic acid) porphine-transitionmetal], abbreviated as [TBSAP-transition metal], and any combinationthereof,

where, in each metalloporphyrin complex the transition metal is cobalt[Co], nickel [Ni], iron [Fe], zinc [Zn], or copper [Cu].

Additional exemplary metalloporphyrin complexes which are suitable forimplementing the present invention are selected from the groupconsisting of chlorophylls [magnesium (II) complexes], hemes [iron (II)complexes], cytochromes (e.g., cytochrome P450, and cytochrome P430),and any combination thereof. An exemplary metallocorrin complex which issuitable for implementing the present invention is vitamin B₁₂ [corrinligand (porphyrin analog) complexed to a cobalt (III) ion].

The zero valent metal composite, optionally, additionally includesvermiculite.

The method for manufacturing the zero valent metal composite, of thepresent invention, includes the main procedure of incorporating zerovalent metal particles having a size in a range of between about 1 nmand about 1000 nm and at least one electron transfer mediator on or/andin a powdered diatomite matrix. In a preferred embodiment, the procedureof incorporating the zero valent metal particles and the at least oneelectron transfer mediator on or/and in the powdered diatomite matrix isperformed by the following exemplary order or sequence of procedures(a)-(i): (a) preparing an aqueous solution of a metal salt; (b)preparing an aqueous solution of the at least one electron transfermediator; (c) adding the aqueous solution of the at least one electrontransfer mediator to the aqueous solution of the metal salt, for formingan aqueous solution of the metal salt and the at least one electrontransfer mediator; (d) adding the powdered diatomite matrix to theaqueous solution of the metal salt and the at least one electrontransfer mediator, for forming an aqueous slurry of the metal salt, theat least one electron transfer mediator, and the powdered diatomitematrix; (e) preparing an aqueous solution of a strong reducing agent;(f) forming and initiating reaction of a redox reaction mixture of theaqueous slurry of the metal salt, the at least one electron transfermediator, and the powdered diatomite matrix, with the aqueous solutionof the strong reducing agent; (g) allowing the redox reaction mixture toreact to completion, for forming a product mixture of the zero valentmetal composite in water; (h) collecting the zero valent metalcomposite; and (i) drying the collected zero valent metal composite, forforming dry zero valent metal composite.

The method for manufacturing the zero valent metal composite of thepresent invention, optionally, further includes adding vermiculite, forforming the zero valent metal composite composed of the powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having the size in the range of between about 1 nm and about1000 nm and the at least one electron transfer mediator, and includesvermiculite. In a first exemplary alternative preferred embodiment ofthe manufacturing method, adding vermiculite is included as a procedure,for example, as (a′), following (a) of preparing an aqueous solution ofa metal salt, and before (b) of preparing an aqueous solution of the atleast one electron transfer mediator. In a second exemplary alternativepreferred embodiment of the manufacturing method, the step of addingvermiculite is included as a procedure, for example, as procedure (h′),following procedure (h) of collecting the zero valent metal composite,and before procedure (i) of drying the collected zero valent metalcomposite.

The method for catalytically treating contaminated water, of the presentinvention, includes the main procedure of exposing the contaminatedwater to a catalytically effective amount of the zero valent metalcomposite, to thereby decrease concentration of at least one contaminantin the contaminated water. Preferably, exposing the contaminated waterto the zero valent metal composite is performed in a manner, forexample, under anaerobic conditions, such that only contaminants in thecontaminated water, and not non-contaminant species (such as oxygen gas)in the contaminated water or/and in the immediate vicinity of thecontaminated water, are catalytically reduced by the zero valent metalparticles in the composite. The components of the zero valent metalcomposite, singly, or in a synergistic combination, catalyticallydecrease contaminant concentrations in contaminated water.

The system for catalytically treating contaminated water, of the presentinvention, includes the main components of: (a) the zero valent metalcomposite, and (b) at least one in-situ or/and ex-situ unit forcontaining a catalytically effective amount of the zero valent metalcomposite, for exposing the contaminated water to the zero valent metalcomposite. Exemplary applicable in-situ units for containing the zerovalent metal composite are either in a form as at least part of asub-surface water permeable reactive barrier (PRB) configured as acontinuous filled in trench, wall, or stand-alone well, or, in a form aspart of a sub-surface water pumping and treatment system. An exemplaryapplicable ex-situ unit for containing the zero valent metal compositeis in a form as part of an above-surface reactor which is part of anabove-surface water pumping and treatment system. For treatingcontaminated water particularly being a form of water vapor or/andgaseous water, an exemplary applicable in-situ or ex-situ unit forcontaining the zero valent metal composite is in a form as part of avariably locatable (sub-surface or above-surface) water treatmentreactor system.

Exposing contaminated water to the zero valent metal composite of thepresent invention can be performed according to any of a variety ofdifferent ways. For implementing the present invention, preferably, themanner of exposure is such that the contaminated water, for example, inthe form of contaminated sub-surface water, surface water, orabove-surface water, naturally or forcibly, flows through, and isbrought into physicochemical contact with, the zero valent metalcomposite while the zero valent metal composite remains essentiallystationary. Moreover, preferably, the manner of exposure is such thatthe volumetric or mass flow rate of the contaminated water, naturally orforcibly, flowing through the zero valent metal composite is at leastequal to or larger than the volumetric or mass flow rate of thecontaminated water, naturally or forcibly, flowing through the ground ormaterial immediately surrounding the zero valent metal composite.Accordingly, preferably, the manner of exposure is such that thepermeability, k, of the zero valent metal composite is at least equal toor larger than the permeability, k, of the ground or materialimmediately surrounding the zero valent metal composite.

The article-of-manufacture, of the present invention, includes apackaging material, and the hereinabove illustratively described zerovalent metal composite composed of a powdered diatomite matrix on or/andin which is incorporated zero valent metal particles having a size in arange of between about 1 nm and about 1000 nm and at least one electrontransfer mediator, being contained within the packaging material, thecomposite being identified for use in catalytically treatingcontaminated water. In a particular embodiment of the present invention,the article-of-manufacture includes a packaging material, and thehereinabove illustratively described zero valent metal compositecomposed of a composition consisting essentially of a powdered diatomitematrix on or/and in which is incorporated zero valent metal particleshaving a size in a range of between about 1 nm and about 1000 nm and atleast one electron transfer mediator, being contained within thepackaging material, the composite being identified for use incatalytically treating contaminated water.

Thus, according to the present invention, there is provided a zerovalent metal composite comprising a powdered diatomite matrix on or/andin which is incorporated zero valent metal particles having a size in arange of between about 1 nm and about 1000 nm and at least one electrontransfer mediator.

According to another aspect of the present invention, there is provideda zero valent metal composite comprising a composition consistingessentially of a powdered diatomite matrix on or/and in which isincorporated zero valent metal particles having a size in a range ofbetween about 1 nm and about 1000 nm and at least one electron transfermediator.

According to another aspect of the present invention, there is provideda method for manufacturing a zero valent metal composite, the methodcomprising incorporating zero valent metal particles having a size in arange of between about 1 nm and about 1000 nm and at least one electrontransfer mediator on or/and in a powdered diatomite matrix.

According to another aspect of the present invention, there is provideda method for catalytically treating contaminated water, the methodcomprising exposing the contaminated water to a catalytically effectiveamount of a zero valent metal composite composed of a powdered diatomitematrix on or/and in which is incorporated zero valent metal particleshaving a size in a range of between about 1 nm and about 1000 nm and atleast one electron transfer mediator, to thereby decrease concentrationof at least one contaminant in the contaminated water.

According to another aspect of the present invention, there is provideda system for catalytically treating contaminated water, comprising: (a)a zero valent metal composite comprised of a powdered diatomite matrixon or/and in which is incorporated zero valent metal particles having asize in a range of between about 1 nm and about 1000 nm and at least oneelectron transfer mediator, and (b) at least one unit for containing acatalytically effective amount of the zero valent metal composite, forexposing the contaminated water to the zero valent metal composite.

According to another aspect of the present invention, there is providedan article-of-manufacture comprising a packaging material, and the abovedescribed zero valent metal composite comprising a powdered diatomitematrix on or/and in which is incorporated zero valent metal particleshaving a size in a range of between about 1 nm and about 1000 nm and atleast one electron transfer mediator, being contained within thepackaging material, the composite being identified for use incatalytically treating contaminated water.

According to another aspect of the present invention, there is providedan article-of-manufacture comprising a packaging material, and the abovedescribed zero valent metal composite comprising a compositionconsisting essentially of a powdered diatomite matrix on or/and in whichis incorporated zero valent metal particles having a size in a range ofbetween about 1 nm and about 1000 nm and at least one electron transfermediator, being contained within the packaging material, the compositebeing identified for use in catalytically treating contaminated water.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is herein described, by way of example only, withreference to the accompanying drawings. With specific reference now tothe drawings in detail, it is stressed that the particulars shown are byway of example and for purposes of illustrative description of thepreferred embodiments of the present invention only, and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of the principles and conceptual aspectsof the present invention. In this regard, no attempt is made to showstructural details of the present invention in more detail than isnecessary for a fundamental understanding of the invention, thedescription taken with the drawings making apparent to those skilled inthe art how the several forms of the invention may be embodied inpractice. In the drawings:

FIGS. 1A and 1B are SEM (scanning electron microscope) photographsshowing a 5 μm and 1 μm scale, respectively, of a portion of a ‘clean’(pretreated, pre-reacted) powdered diatomite used for manufacturing(synthesizing) different specific embodiments of an exemplary zerovalent metal composite, being a zero valent iron composite, as describedhereinbelow and exemplified in Examples 1, 2, and 3, in accordance withthe present invention;

FIGS. 2A and 2B are SEM photographs showing a 5 μm and 1 μm scale,respectively, of a portion of an exemplary zero valent metal composite,being the (dry) zero valent iron composite manufactured (synthesized) asdescribed hereinbelow and exemplified in Example 1, composed of apowdered diatomite matrix on or/and in which is incorporated zero valentiron particles having a size in a range of between about 1 nm and about1000 nm and vitamin B₁₂ (metallocorrin complex type of porphyrinogenicorganometallic complex, as an exemplary electron transfer mediator), inaccordance with the present invention;

FIG. 3 is a SEM photograph showing a 5 μm scale of a portion of anexemplary ‘comparative reference’ zero valent metal composite (withoutan electron transfer mediator), being a (dry) zero valent iron compositemanufactured (synthesized) ‘similar’ to that as described hereinbelowand exemplified in Example 1, composed of a powdered diatomite matrix onor/and in which is incorporated zero valent iron particles (aggregates)having an average size larger than about 600 nm, without an electrontransfer mediator, for serving as an exemplary reference zero valentmetal composite when compared to the exemplary zero valent metalcomposite of the present invention which appears in the SEM photographsof FIGS. 2A and 2B;

FIG. 4 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, wherein the contaminated water is in theform of a natural flow of sub-surface water, and the catalyticallyeffective amount of the zero valent metal composite is dispersedthroughout and contained within an in-situ unit being in a form as thelower portion of a sub-surface water permeable reactive barrier (PRB)configured as a continuous filled in trench or wall, in accordance withthe present invention;

FIG. 5 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, wherein the contaminated water is in theform of a natural flow of sub-surface water, and the catalyticallyeffective amount of the zero valent metal composite is dispersedthroughout and contained within each of a plurality of in-situ unitseach being in a form as a sub-surface water permeable reactive barrier(PRB) configured as a stand-alone filled in well, in accordance with thepresent invention;

FIG. 6 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, wherein the contaminated water is in theform of a natural flow of sub-surface water, and the catalyticallyeffective amount of the zero valent metal composite is dispersedthroughout and contained within an in-situ unit being in a form as partof a sub-surface water pumping and treatment system, in accordance withthe present invention;

FIG. 7 is a schematic diagram illustrating a cut-away view of threeexemplary specific configurations, of exemplary specific preferredembodiments of implementing the method and system for catalyticallytreating contaminated water, according to heterogeneous catalysis, via abatch or flow mode, wherein the contaminated water is in the form(s) of(natural or/and forced) flow of sub-surface water, surface water, or/andabove-surface water, and the catalytically effective amount of the zerovalent metal composite is dispersed throughout and contained within anex-situ unit being in a form as part of an above-surface water treatmentreactor system, in accordance with the present invention;

FIG. 8 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, wherein the contaminated water is in theform of water vapor or/and gaseous water, and the catalyticallyeffective amount of the zero valent metal composite is dispersedthroughout and contained within an in-situ or ex-situ unit being in aform as part of a variably locatable (sub-surface or above-surface)water treatment reactor system, in accordance with the presentinvention;

FIGS. 9A and 9B are TEM (transmission electron microscope) photographsshowing a 500 nm and 100 nm scale, respectively, of an aqueoussuspension sample (stored for several days at room conditions) of thezero valent iron composite manufactured (synthesized) as describedhereinbelow and exemplified in Example 1, and which appears in the SEMphotographs of FIGS. 2A and 2B, in accordance with the presentinvention; and

FIGS. 10A and 10B are TEM photographs showing a 5 nm and 10 nm scale,respectively, of the aqueous suspension sample of the zero valent ironcomposite which appears in the TEM photographs of FIGS. 9A and 9B, inaccordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a zero valent metal composite, a methodfor manufacturing thereof, a method using thereof, a system includingthereof, and an article-of-manufacture including thereof. The zerovalent metal composite is used for (in-situ or ex-situ) catalyticallytreating contaminated water. The present invention is generallyapplicable to (in-situ or ex-situ) catalytically treating any of a widevariety of different forms of contaminated water, for example,sub-surface water, surface water, above-surface water, water vapor,gaseous water, or any combination thereof, which are contaminated withany number of a wide variety of different types or kinds of organicor/and inorganic chemical contaminants. The present invention isparticularly applicable to (in-situ or ex-situ) catalytically treatingsuch forms of contaminated water wherein the water contaminants areorganic species, for example, halogenated organic compounds and halogencontaining degradation products thereof; inorganic species, for example,metal elements, metal element containing inorganic species, nonmetalelements, and nonmetal element containing inorganic species; or anycombination thereof. The present invention is also applicable to(in-situ or ex-situ) catalytically treating contaminated non-aqueousfluids (in liquid, vapor, or/and gaseous forms), for decreasingcontaminant concentrations therefrom.

The zero valent metal composite, of the present invention, is composedof a powdered diatomite matrix on or/and in which is incorporated zerovalent metal particles having a size in a range of between about 1 nmand about 1000 nm and at least one electron transfer mediator. In aparticular embodiment of the present invention, the zero valent metalcomposite is composed of a composition consisting essentially of apowdered diatomite matrix on or/and in which is incorporated zero valentmetal particles having a size in a range of between about 1 nm and about1000 nm and at least one electron transfer mediator.

Exemplary applicable zero valent metals are zero valent transitionmetals, for example, iron, cobalt, nickel, copper, zinc, palladium,platinum, gold, or any combination thereof.

In general, essentially any electron transfer mediator functioning as anactive redox catalyst under reducing (anaerobic or anoxic) conditionscan be used for implementing the present invention. Preferably, the atleast one electron transfer mediator is selected from the groupconsisting of a porphyrinogenic organometallic complex, an analogthereof, a derivative thereof, and any combination thereof. Forimplementing the present invention, preferably, the at least oneporphyrinogenic organometallic complex is selected from the groupconsisting of metalloporphyrin complexes, metallocorrin complexes,metallochlorin complexes, and any combination thereof.

Preferably, the metalloporphyrin complex is composed of a transitionmetal complexed to a (initially free base) porphyrin selected from thegroup consisting of:

tetramethylpyridilporphyrin[5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphine], abbreviated as[TMPyP],

tetrahydroxyphenylporphyrin[5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine], abbreviated as[TP(OH)P],

tetraphenylporphyrin [5,10,15,20-tetraphenyl-21H,23H-porphine],abbreviated as [TPP], and

meso-tetraphenylporphyrin-4,4′,4″,4′″-tetrasulfonic acid[5,10,15,20-tetrakis(benzenesulfonic acid) porphine], abbreviated as[TBSAP].

The transition metal is essentially any transition metal capable ofcomplexing with the just stated porphyrins for forming the correspondingmetalloporphyrin complex. Preferably, the transition metal is selectedfrom the group consisting of cobalt [Co], nickel [Ni], iron [Fe], zinc[Zn], and copper [Cu].

Accordingly, for implementing the present invention, preferably, themetalloporphyrin complexes are selected from the group consisting of:

tetramethylpyridilporphyrin-transition metal[5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphine-transition metal],abbreviated as [TMPyP-transition metal],

tetrahydroxyphenylporphyrin-transition metal[5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine-transitionmetal], abbreviated as [TP(OH)P-transition metal],

tetraphenylporphyrin-transition metal[5,10,15,20-tetraphenyl-21H,23H-porphine-transition metal], abbreviatedas [TPP-transition metal],

meso-tetraphenylporphyrin-4,4′,4″,4′″-tetrasulfonic acid-transitionmetal [5,10,15,20-tetrakis (benzenesulfonic acid) porphine-transitionmetal], abbreviated as [TBSAP-transition metal], and any combinationthereof,

where, in each metalloporphyrin complex the transition metal is cobalt[Co], nickel [Ni], iron [Fe], zinc [Zn], or copper [Cu].

Additional exemplary metalloporphyrin complexes which are suitable forimplementing the present invention are selected from the groupconsisting of chlorophylls [magnesium (II) complexes], hemes [iron (II)complexes], cytochromes (e.g., cytochrome P450, and cytochrome P430),and any combination thereof. An exemplary metallocorrin complex which issuitable for implementing the present invention is vitamin B₁₂ [corrinligand (porphyrin analog) complexed to a cobalt (III) ion].

The zero valent metal composite, optionally, additionally includesvermiculite.

The method for manufacturing the zero valent metal composite, of thepresent invention, includes the main procedure of incorporating zerovalent metal particles having a size in a range of between about 1 nmand about 1000 nm and at least one electron transfer mediator on or/andin a powdered diatomite matrix. In a preferred embodiment, the procedureof incorporating the zero valent metal particles and the at least oneelectron transfer mediator on or/and in the powdered diatomite matrix isperformed by the following exemplary order or sequence of procedures(a)-(i): (a) preparing an aqueous solution of a metal salt; (b)preparing an aqueous solution of the at least one electron transfermediator; (c) adding the aqueous solution of the at least one electrontransfer mediator to the aqueous solution of the metal salt, for formingan aqueous solution of the metal salt and the at least one electrontransfer mediator; (d) adding the powdered diatomite matrix to theaqueous solution of the metal salt and the at least one electrontransfer mediator, for forming an aqueous slurry of the metal salt, theat least one electron transfer mediator, and the powdered diatomitematrix; (e) preparing an aqueous solution of a strong reducing agent;(f) forming and initiating reaction of a redox reaction mixture of theaqueous slurry of the metal salt, the at least one electron transfermediator, and the powdered diatomite matrix, with the aqueous solutionof the strong reducing agent; (g) allowing the redox reaction mixture toreact to completion, for forming a product mixture of the zero valentmetal composite in water; (h) collecting the zero valent metalcomposite; and (i) drying the collected zero valent metal composite, forforming dry zero valent metal composite.

The method for manufacturing the zero valent metal composite of thepresent invention, optionally, further includes adding vermiculite, forforming the zero valent metal composite composed of the powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having the size in the range of between about 1 nm and about1000 nm and the at least one electron transfer mediator, and includesvermiculite. In a first exemplary alternative preferred embodiment ofthe manufacturing method, adding vermiculite is included as a procedure,for example, as (a′), following (a) of preparing an aqueous solution ofa metal salt, and before (b) of preparing an aqueous solution of the atleast one electron transfer mediator. In a second exemplary alternativepreferred embodiment of the manufacturing method, the step of addingvermiculite is included as a procedure, for example, as procedure (h′),following procedure (h) of collecting the zero valent metal composite,and before procedure (i) of drying the collected zero valent metalcomposite.

The method for catalytically treating contaminated water, of the presentinvention, includes the main procedure of exposing the contaminatedwater to a catalytically effective amount of the zero valent metalcomposite, to thereby decrease concentration of at least one contaminantin the contaminated water. Preferably, exposing the contaminated waterto the zero valent metal composite is performed in a manner, forexample, under anaerobic conditions, such that only contaminants in thecontaminated water, and not non-contaminant species (such as oxygen gas)in the contaminated water or/and in the immediate vicinity of thecontaminated water, are catalytically reduced by the zero valent metalparticles in the composite. The components of the zero valent metalcomposite, singly, or in a synergistic combination, catalyticallydecrease contaminant concentrations in contaminated water.

The system for catalytically treating contaminated water, of the presentinvention, includes the main components of: (a) the zero valent metalcomposite, and (b) at least one in-situ or/and ex-situ unit forcontaining a catalytically effective amount of the zero valent metalcomposite, for exposing the contaminated water to the zero valent metalcomposite. Exemplary applicable in-situ units for containing the zerovalent metal composite are either in a form as at least part of asub-surface water permeable reactive barrier (PRB) configured as acontinuous filled in trench, wall, or stand-alone well, or, in a form aspart of a sub-surface water pumping and treatment system. An exemplaryapplicable ex-situ unit for containing the zero valent metal compositeis in a form as part of an above-surface reactor which is part of anabove-surface water pumping and treatment system. For treatingcontaminated water particularly being a form of water vapor or/andgaseous water, an exemplary applicable in-situ or ex-situ unit forcontaining the zero valent metal composite is in a form as part of avariably locatable (sub-surface or above-surface) water treatmentreactor system.

Exposing contaminated water to the zero valent metal composite of thepresent invention can be performed according to any of a variety ofdifferent ways. For implementing the present invention, preferably, themanner of exposure is such that the contaminated water, for example, inthe form of contaminated sub-surface water, surface water, orabove-surface water, naturally or forcibly, flows through, and isbrought into physicochemical contact with, the zero valent metalcomposite while the zero valent metal composite remains essentiallystationary. Moreover, preferably, the manner of exposure is such thatthe volumetric or mass flow rate of the contaminated water, naturally orforcibly, flowing through the zero valent metal composite is at leastequal to or larger than the volumetric or mass flow rate of thecontaminated water, naturally or forcibly, flowing through the ground ormaterial immediately surrounding the zero valent metal composite.Accordingly, preferably, the manner of exposure is such that thepermeability, k, of the zero valent metal composite is at least equal toor larger than the permeability, k, of the ground or materialimmediately surrounding the zero valent metal composite.

The article-of-manufacture, of the present invention, includes apackaging material, and the hereinabove illustratively described zerovalent metal composite composed of a powdered diatomite matrix on or/andin which is incorporated zero valent metal particles having a size in arange of between about 1 nm and about 1000 nm and at least one electrontransfer mediator, being contained within the packaging material, thecomposite being identified for use in catalytically treatingcontaminated water. In a particular embodiment of the present invention,the article-of-manufacture includes a packaging material, and thehereinabove illustratively described zero valent metal compositecomposed of a composition consisting essentially of a powdered diatomitematrix on or/and in which is incorporated zero valent metal particleshaving a size in a range of between about 1 nm and about 1000 nm and atleast one electron transfer mediator, being contained within thepackaging material, the composite being identified for use incatalytically treating contaminated water.

The present invention includes several aspects of novelty andinventiveness over prior art teachings of zero valent metal compositematerials, manufacturing zero valent metal composite materials, methodsusing zero valent composite materials, systems including zero valentmetal composite materials, and articles-of-manufacture including zerovalent metal composite materials, in the relevant fields and artsthereof.

It is to be understood that the present invention is not limited in itsapplication to the details of the compositions, structures, components,and types, of the zero valent metal composite, or of thearticle-of-manufacture including the zero valent metal composite, or tothe details of the order or sequence, and number, of procedures, steps,and sub-steps, peripheral equipment, utilities, accessories, chemicalreagents, and materials, of operation or implementation of the methods,or to the details of type, composition, construction, arrangement,order, and number, of the system units, system sub-units, devices,assemblies, sub-assemblies, mechanisms, structures, components,elements, and configurations, and, peripheral equipment, utilities,accessories, and materials, of the system, set forth in the followingillustrative description, accompanying drawings, and examples, unlessotherwise specifically stated herein. Moreover, although the presentinvention is primarily focused on applications involving treatment ofcontaminated water, wherein the contaminated water is, for example, aform of sub-surface water, surface water, above-surface water, watervapor, gaseous water, or any combination thereof, it is to be fullyunderstood that the present invention is also applicable tocatalytically treating contaminated non-aqueous fluids (in liquid,vapor, or/and gaseous forms), for decreasing contaminant concentrationstherefrom.

Accordingly, the present invention is capable of other embodiments andof being practiced or carried out in various ways. Althoughcompositions, structures, components, and types, of the zero valentmetal composite, or of the article-of-manufacture including the zerovalent metal composite, or orders or sequences, and numbers, ofprocedures, steps, and sub-steps, peripheral equipment, utilities,accessories, chemical reagents, and materials, of operation orimplementation of the disclosed methods, or types, compositions,constructions, arrangements, orders, and numbers, of system units,system sub-units, devices, assemblies, sub-assemblies, mechanisms,structures, components, elements, and configurations, and, peripheralequipment, utilities, accessories, and materials, of the disclosedsystem, which are equivalent or similar to those illustrativelydescribed and exemplified herein can be used for practicing or testingthe present invention, suitable compositions, structures, components,and types, of the zero valent metal composite, or of thearticle-of-manufacture including the zero valent metal composite, ororders or sequences, and numbers, of procedures, steps, and sub-steps,peripheral equipment, utilities, accessories, chemical reagents, andmaterials, of operation or implementation of the disclosed methods, ortypes, compositions, constructions, arrangements, orders, and numbers,of system units, system sub-units, devices, assemblies, sub-assemblies,mechanisms, structures, components, elements, and configurations, and,peripheral equipment, utilities, accessories, and materials, of thedisclosed system, are illustratively described and exemplified herein.

It is also to be understood that all technical and scientific words,terms, or/and phrases, used herein throughout the present disclosurehave either the identical or similar meaning as commonly understood byone of ordinary skill in the art to which this invention belongs, unlessotherwise specifically defined or stated herein. Phraseology,terminology, and, notation, employed herein throughout the presentdisclosure are for the purpose of description and should not be regardedas limiting. Moreover, all technical and scientific words, terms, or/andphrases, introduced, defined, described, or/and exemplified, in theabove Background section, are equally or similarly applicable in theillustrative description of the preferred embodiments, examples, andappended claims, of the present invention. As used herein, the term‘about’ refers to ±10% of the associated value. Additionally, as usedherein, the phrase ‘room temperature’ refers to a temperature in a rangeof between about 20° C. and about 25° C. The following notation is usedthroughout the present disclosure: %=percent; ppm=parts per million;Å=angstroms; nm=nanometers; mg=milligrams; l=liter; mg/l=milligrams perliter; ml=milliliter; and rpm=rounds per minute.

Exemplary preferred embodiments, alternative preferred embodiments,specific configurations, and, additional and optional aspects,characteristics, or features, thereof, of compositions, structures,components, and types, of the zero valent metal composite, and of thearticle-of-manufacture including the zero valent metal composite, and,the order or sequence, and number, of procedures, steps, and sub-steps,peripheral equipment, utilities, accessories, chemical reagents, andmaterials, of operation or implementation of the methods, and, the type,composition, construction, arrangement, order, and number, of the systemunits, system sub-units, devices, assemblies, sub-assemblies,mechanisms, structures, components, elements, and configurations, and,peripheral equipment, utilities, accessories, and materials, of thesystem, for (in-situ or ex-situ) catalytically treating contaminatedwater, according to the present invention, are better understood withreference to the following illustrative description and accompanyingdrawings. Throughout the following illustrative description andaccompanying drawings, same reference numbers refer to same structures,components, or elements.

In the following illustrative description of the present invention,included are main or principal compositions, structures, components, andtypes, of the zero valent metal composite, and, of thearticle-of-manufacture including the zero valent metal composite, and,main or principal orders or sequences, and numbers, of procedures,steps, and sub-steps, peripheral equipment, utilities, accessories,chemical reagents, and materials, of operation or implementation of thedisclosed methods, and, main or principal types, compositions,constructions, arrangements, orders, and numbers, of system units,system sub-units, devices, assemblies, sub-assemblies, mechanisms,structures, components, elements, and configurations, and, peripheralequipment, utilities, accessories, and materials, of the disclosedsystem, needed for sufficiently understanding proper ‘enabling’utilization and implementation of the disclosed invention. Accordingly,description of various possible preliminary, intermediate, minor, or/andoptional, compositions, structures, components, and types, of the zerovalent metal composite, and, of the article-of-manufacture including thezero valent metal composite, and, main or principal orders or sequences,and numbers, of procedures, steps, and sub-steps, peripheral equipment,utilities, accessories, chemical reagents, and materials, of operationor implementation of the disclosed methods, and, main or principaltypes, compositions, constructions, arrangements, orders, and numbers,of system units, system sub-units, devices, assemblies, sub-assemblies,mechanisms, structures, components, elements, and configurations, and,peripheral equipment, utilities, accessories, and materials, of thedisclosed system, of secondary importance with respect to enablingimplementation of the invention, which are readily known by one ofordinary skill in the art, or/and which are available in the relevantprior art and technical literature, are at most only briefly indicatedherein.

Thus, according to a main aspect of the present invention, there isprovision of a zero valent metal composite composed of a powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having a size in a range of between about 1 nm and about 1000nm and at least one electron transfer mediator.

Following are selected details regarding types, and, structuralproperties and parameters, of the components of the zero valent metalcomposite of the present invention.

Unless otherwise explicitly stated, the hereinbelow described andnumerically valued structural properties and parameters, in particular,particle size, pore size, and concentration (in terms of weight (mass)percent), of the components of the zero valent metal composite, are withrespect to a ‘dry basis’. As used herein, a dry basis means that anumerical value of a structural property or parameter of a component ofthe zero valent metal composite is evaluated from empirical or/andtheoretical data and information obtained from, and corresponding to,the zero valent metal composite, or/and components thereof, being eitherin a ‘dry’ (water-free) environment or in an environment of roomtemperature (20-25° C.) and room pressure (about 1 atmosphere). In otherwords, the numerical values of these particular structural properties orparameters of a component of the zero valent metal composite are ‘not’evaluated from empirical or/and theoretical data and informationobtained from, or corresponding to, the zero valent metal composite,or/and components thereof, being in a ‘wet’ (for example, water filled)environment. By contrast, for example, the physicochemical property orparameter of permeability, k, of the zero valent metal composite,defined and described hereinbelow, is evaluated from empirical or/andtheoretical data and information obtained from, or corresponding to, thezero valent metal composite, and components thereof, being in a ‘wet’(water filled and flowing) environment.

Powdered Diatomite Matrix Included in the Zero Valent Metal Composite:

The powdered diatomite matrix included in the zero valent metalcomposite originates from a powdered form of the well known and readilyavailable diatomite, also known as diatomaceous earth or kieselguhr,being a porous, chalk-like, sedimentary rock, formed by fossilaccumulation of diatoms in the form of amorphous, hydrated silica. Thepowdered diatomite matrix is highly absorbent, physically and chemicallystable, nearly indestructible, and ordinarily chemically inert to mostcommon water contaminants.

The particle size, in terms of a ‘characteristic’ particle sizedimension, of the particles of the powdered diatomite matrix included inthe zero valent metal composite, on a dry basis, is in a range ofbetween about 1 micron and about 150 microns. More preferably, theparticle size of the powdered diatomite matrix particles is in a rangeof between about 5 microns and about 100 microns, and most preferably,is in a range of between about 20 microns and about 50 microns. Takinginto account non-uniform or/and irregular geometrical shapes of theparticles, a characteristic particle size dimension of the particles ofthe powdered diatomite matrix can be considered to be, for example, thelongest distance (long distance) or longest diameter (long diameter)spanning across two ends of a diatomite particle.

The pore size, in terms of a ‘characteristic’ pore size dimension, ofthe pores of the particles of the powdered diatomite matrix included inthe zero valent metal composite, on a dry basis, is in a range ofbetween about 1 nm and about 5000 nm. More preferably, the pore size ofthe pores of the powdered diatomite matrix particles is in a range ofbetween about 50 nm and about 3000 nm, and most preferably, is in arange of between about 100 nm and about 2000 nm. Taking into accountnon-uniform or/and irregular geometrical shapes of the pores of theparticles, a characteristic pore size dimension of the pores of theparticles of the powdered diatomite matrix can be considered to be, forexample, the longest distance (long distance) or longest diameter (longdiameter) spanning across two ends of a pore of a diatomite particle.

Zero Valent Metal Particles Included in the Zero Valent Metal Composite:

Preferably, the zero valent metal particles which are incorporated onor/and in the powdered diatomite matrix of the zero valent metalcomposite are of at least one zero valent metal selected from the groupconsisting of zero valent transition metals. Preferably, the at leastone zero valent metal which is applicable for implementing the presentinvention is at least one zero valent transition metal selected from thegroup consisting of iron, cobalt, nickel, copper, zinc, palladium,platinum, gold, and any combination thereof. More preferably, the zerovalent transition metal which is used for implementing the presentinvention is iron.

As stated, the particle size, in terms of a ‘characteristic’ particlesize dimension, of the zero valent metal particles incorporated onor/and in the powdered diatomite matrix of the zero valent metalcomposite, on a dry basis, is in a range of between about 1 nm and about1000 nm. More preferably, the particle size of the zero valent metalparticles is in a range of between about 5 nm and about 500 nm, and mostpreferably, is in a range of between about 20 nm and about 200 nm.Taking into account non-uniform or/and irregular geometrical shapes ofthe particles, a characteristic particle size dimension of the particlesof the zero valent metal can be considered to be, for example, thelongest distance (long distance) or longest diameter (long diameter)spanning across two ends of a zero valent metal particle.

The concentration, in terms of weight (mass) percent, of the zero valentmetal particles incorporated on or/and in the powdered diatomite matrixof the zero valent metal composite, on a dry basis, is in a range ofbetween about 0.1% and about 20%. More preferably, the weight percent ofthe zero valent metal particles is in a range of between about 0.5% andabout 15%, and most preferably, is in a range of between about 1% andabout 10%. As used herein, the concentration, in terms of weightpercent, of the zero valent metal particles incorporated on or/and inthe powdered diatomite matrix of the zero valent metal compositecorresponds to the weight of the zero valent metal particles as apercent of the total weight of the zero valent metal composite, whichcan be written as (weight of the zero valent metal particles/totalweight of the zero valent metal composite)×100.

Electron Transfer Mediator Included in the Zero Valent Metal Composite:

As used herein, an ‘electron transfer mediator’ is a chemical substance,functioning as a catalyst or co-catalyst, which is catalytically active,and expedites (catalyzes) redox (reduction-oxidation) types of chemicalreactions, such as reductive dehalogenation, by participating in,mediating, and expediting, the transfer of electrons from a bulkelectron donor or reducing agent to an electron acceptor, or/and bystabilizing intermediate forms of the redox reactants. An electrontransfer mediator which specifically functions by participating in,mediating, and expediting, the transfer of electrons from an electrondonor or reducing agent to an electron acceptor is also known as anelectron carrier or as an electron shuttle, since electrons are carriedand shuttled by such a chemical species. Description, general mechanisms(with reference to chemical equations (1) and (2)), and prior artteachings, of reductive dehalogenation, in general, and of zero valentmetal (ZVM) reductive dehalogenation, in particular, of halogenatedorganic compounds, catalyzed by an electron transfer mediator catalyst,are provided hereinabove in the Background section.

In general, essentially any electron transfer mediator functioning as anactive redox catalyst under reducing (anaerobic or anoxic) conditionscan be used for implementing the present invention. Preferably, the atleast one electron transfer mediator is selected from the groupconsisting of at least one porphyrinogenic organometallic complex, atleast one analog thereof, at least one derivative thereof, and anycombination thereof.

As used herein, a ‘porphyrinogenic organometallic complex’ means anorganometallic complex formed between a neutral metal atom or a metalion and a porphyrinogenic or porphyrinogenic-like ring system. As usedherein, a ‘porphyrinogenic or porphyrinogenic-like ring system’ means asystem in which 5-membered heterocyclic rings are linked in amacrocyclic ring structure by linking groups. The linking groups aresaturated or/and unsaturated and have saturated or/and unsaturated sidechains such that a complete or partial pi-conjugation is formed betweenthe macrocyclic rings and the unsaturated linking groups or/and sidechains in the system. The porphyrinogenic or porphyrinogenic-like ringsystem preferably also has sufficient non-conjugated electrons to formcovalent or coordinate bonds with the metal.

It is to be fully understood that the term ‘porphyrinogenicorganometallic complex’ as used herein encompasses an organometalliccomplex formed between a neutral metal atom or a metal ion, and ananalog or derivative of the just defined porphyrinogenic orporphyrinogenic-like ring system.

As used herein, the term ‘analog’ of a subject (parent) compound refersto a compound whose molecular structure is structurally related oranalogous to the subject (parent) compound molecular structure, andtherefore, such a compound is expected to exhibit similar (physical,or/and chemical, or/and biological) activity(ies) as that exhibited bythe subject (parent) compound.

As used herein, the term ‘derivative’ of a subject (parent) compoundrefers to a compound whose molecular structure is derived as a result of‘chemical modification’ of the molecular structure of the subject(parent) compound, such that a major portion of the subject (parent)compound molecular structure remains unchanged or intact in themolecular structure of the derivative compound. The chemicalmodification of the molecular structure of the subject (parent) compoundtakes place in an active manner, e.g., using synthetic organic chemistrymethods and techniques, for forming an active type of derivative of thesubject (parent) compound. Alternatively, or additionally, the chemicalmodification of the molecular structure of the subject (parent) compoundtakes place in a passive manner, i.e., using naturally occurring methodsand techniques, for forming a passive type of derivative of the subject(parent) compound. For example, a compound whose molecular structure isderived by (active or/and passive) addition of at least one substituentto, or/and by a change of at least one substituent from, the molecularstructure of a subject (parent) compound. For example, a compound whosemolecular structure is derived by (active or/and passive) oxidation orhydrolysis of molecules of a subject (parent) compound.

The preceding definitions of analog and derivative of a subject compoundare applicable to analogs and derivatives, respectively, of aporphyrinogenic organometallic complex subject (parent) compound.

As previously stated hereinabove in the Background section, there areextensive teachings [e.g., 34] about the origin, and the numerousphysical, chemical, and biological, properties, characteristics, andbehavior, of porphyrinogenic organometallic complexes, of whichthousands have been identified and studied [e.g., 35, 36]. Exemplarywell known metalloporphyrin complexes are chlorophylls, which aremagnesium (II) complexes; hemes, which are iron (II) complexes; andcytochromes (e.g., cytochrome P450, and cytochrome P430). Vitamin B₁₂(cyanocobalamin) a naturally occurring, or synthesized,metalloporphyrin-like complex of related structure and function, is ametallocorrin type of porphyrinogenic organometallic complex composed ofa corrin ligand (a porphyrin analog in which some of the methylenebridges are substituted or/and absent) complexed to a cobalt (III) ion.

Porphyrinogenic organometallic complexes, such as metalloporphyrins,metalloporphyrin-like complexes, and their derivatives, exist in manybiochemical environments, such as living cells, soils, sediments,bitumens, coal, oil shales, petroleum, and other types of naturallyoccurring deposits rich in organic matter [e.g., 37-39]. Porphyrinogenicorganometallic complexes are well known for functioning as electrontransfer mediators, and play an important role in various biochemicalpathways, such as oxygen transport and storage (hemoglobin andmyoglobin, respectively) and electron transfer in redox(reduction-oxidation) reactions (cytochromes).

Porphyrinogenic organometallic complexes exhibit several particularproperties, characteristics, and behavior, which make them especiallywell applicable for functioning as electron transfer mediator typecatalysts in homogeneous or heterogeneous electron transfer mediatedcatalytic reductive dehalogenation (typically, dechlorination) reactionsystems, for catalyzing reductive dehalogenation of halogenated organiccompound contaminants in water under reducing (anaerobic or anoxic)conditions. Porphyrinogenic organometallic complexes are: (1) effectiveredox catalysts for many reactions, and have a long range of redoxactivity; (2) electrochemically active with almost any core metal; (3)active catalysts in aqueous solution under conditions particularlypertinent to environments of various different forms of contaminatedsub-surface water and surface water; and (4) relatively highly stable,thereby enabling reactions to take place under severe conditions, whereother types of reactions probably would not take place.

For implementing the present invention, preferably, the at least oneporphyrinogenic organometallic complex is selected from the groupconsisting of metalloporphyrin complexes, metallocorrin complexes,metallochlorin complexes, and any combination thereof. Metalloporphyrincomplexes (commonly known and referred to as metalloporphyrins), beingporphyrinogenic organometallic complexes of metal ions and porphyrinligands, are organic tetrapyrrole macrocycles composed of four pyrroletype rings joined by methane (methylidene) bridges and complexed to acentral metal ion. They form a near planar structure of aromaticmacrocycles containing up to 22 conjugated π electrons, 18 of which areincorporated into the delocalization pathway in accordance with Huckel's[4n+2] rule of aromaticity. One or two of the peripheral double bonds ofthe porphyrin ligands of a metalloporphyrin can undergo an additionreaction to form a metalloporphyrin derivative, such as a metallocorrinor a metallochlorin type of porphyrinogenic organometallic complex.

Preferably, the metalloporphyrin complex is composed of a transitionmetal complexed to a (initially free base) porphyrin selected from thegroup consisting of:

tetramethylpyridilporphyrin[5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphine], herein,abbreviated as [TMPyP],

tetrahydroxyphenylporphyrin[5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine], herein,abbreviated as [TP(OH)P],

tetraphenylporphyrin [5,10,15,20-tetraphenyl-21H,23H-porphine], herein,abbreviated as [TPP], and

meso-tetraphenylporphyrin-4,4′,4″,4′″-tetrasulfonic acid[5,10,15,20-tetrakis(benzenesulfonic acid) porphine], herein,abbreviated as [TBSAP].

The transition metal is essentially any transition metal capable ofcomplexing with the just stated porphyrins for forming the correspondingmetalloporphyrin complex. Preferably, the transition metal is selectedfrom the group consisting of cobalt [Co], nickel [Ni], iron [Fe], zinc[Zn], and copper [Cu].

Accordingly, for implementing the present invention, preferably, themetalloporphyrin complexes are selected from the group consisting of:

tetramethylpyridilporphyrin-transition metal[5,10,15,20-tetrakis(1-methyl-4-pyridinio)-porphine-transition metal],herein, abbreviated as [TMPyP-transition metal],

tetrahydroxyphenylporphyrin-transition metal[5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphine-transitionmetal], herein, abbreviated as [TP(OH)P-transition metal],

tetraphenylporphyrin-transition metal[5,10,15,20-tetraphenyl-21H,23H-porphine-transition metal], herein,abbreviated as [TPP-transition metal],

meso-tetraphenylporphyrin-4,4′,4″,4′″-tetrasulfonic acid-transitionmetal [5,10,15,20-tetrakis(benzenesulfonic acid)porphine-transitionmetal], herein, abbreviated as [TBSAP-transition metal], and anycombination thereof,

where, in each metalloporphyrin complex the transition metal is cobalt[Co], nickel [Ni], iron [Fe], zinc [Zn], or copper [Cu].

The above indicated [TMPyP-transition metal], [TP(OH)P-transitionmetal], [TPP-transition metal], and [TBSAP-transition metal], preferredmetalloporphyrin complexes are either commercially available, or aresynthesized from the commercially available respective [TMPyP],[TP(OH)P], [TPP], or [TBSAP], (free base) porphyrins and transitionmetal solutions using published methods and techniques [e.g., 54, 55].

Additional exemplary metalloporphyrin complexes which are suitable forimplementing the present invention are selected from the groupconsisting of chlorophylls [magnesium (II) complexes], hemes [iron (II)complexes], cytochromes (e.g., cytochrome P450, and cytochrome P430),and any combination thereof. An exemplary metallocorrin complex which issuitable for implementing the present invention is vitamin B₁₂ [corrinligand (porphyrin analog) complexed to a cobalt (III) ion].

The concentration, in terms of weight percent, of the at least oneelectron transfer mediator incorporated on or/and in the powdereddiatomite matrix of the zero valent metal composite, on a dry basis, isin a range of between about 0.001% and about 1%. More preferably, theweight percent of the electron transfer mediator is in a range ofbetween about 0.005% and about 0.5%, and most preferably, is in a rangeof between about 0.01% and about 0.1%. As used herein, theconcentration, in terms of weight percent, of the electron transfermediator incorporated on or/and in the powdered diatomite matrix of thezero valent metal composite corresponds to the weight of the electrontransfer mediator as a percent of the total weight of the zero valentmetal composite, which can be written as (weight of the electrontransfer mediator/total weight of the zero valent metal composite)×100.

The zero valent metal particles and the at least one electron transfermediator are preferably incorporated on or/and in the powdered diatomitematrix by means of being dispersed throughout the matrix surface or/andpores, supported by the matrix surface or/and pores, adhered in achemical bonding manner to the matrix surface or/and pores, or/andentrapped in the matrix pores.

In a particular embodiment of the present invention, the zero valentmetal composite is composed of a composition consisting essentially of apowdered diatomite matrix on or/and in which is incorporated zero valentmetal particles having a size in a range of between about 1 nm and about1000 nm and at least one electron transfer mediator. This particularembodiment of the zero valent metal composite corresponds to anothermain aspect of the present invention.

FIGS. 1A and 1B are SEM (scanning electron microscope) photographsshowing a 5 μm and 1 μm scale, respectively, of a portion of a ‘clean’(pre-treated, pre-reacted) powdered diatomite used for manufacturing(synthesizing) different specific embodiments of an exemplary zerovalent metal composite, being a zero valent iron composite, as describedherein and exemplified in Examples 1, 2, and 3, in accordance with thepresent invention. FIGS. 2A and 2B are SEM photographs showing a 5 μmand 1 μm scale, respectively, of a portion of an exemplary zero valentmetal composite, being the (dry) zero valent iron composite manufactured(synthesized) as described herein and exemplified in Example 1, composedof a powdered diatomite matrix on or/and in which is incorporated zerovalent iron particles (for example, which appear as white coloredrelatively small circularly shaped spots, as pointed to by the pairedarrows) having a size in a range of between about 1 nm and about 1000 nmand vitamin B₁₂ (metallocorrin complex type of porphyrinogenicorganometallic complex, as an exemplary electron transfer mediator), inaccordance with the present invention.

Comparison of the SEM photographs of FIGS. 2A and 2B with those of FIGS.1A and 1B, respectively, clearly shows that nanometer sized zero valentiron particles are incorporated on or/and in (as described hereinabove)the powdered diatomite matrix of the zero valent iron composite.Elemental analysis of the surface layer of a portion of the zero valentiron composite, encompassing the powdered diatomite matrix and aplurality of the nanometer sized zero valent iron particles, indicatesthe presence of silica and iron. The SEM instrument was unable toresolve elemental analysis at the size scale of individual nanometersized zero valent iron particles observed in the SEM photographs.

FIG. 3 is a SEM photograph showing a 5 μm scale of a portion of anexemplary ‘comparative reference’ zero valent metal composite (withoutan electron transfer mediator), being a (dry) zero valent iron compositemanufactured (synthesized) ‘similar’ to that as described hereinbelowand exemplified in Example 1, composed of a powdered diatomite matrix onor/and in which is incorporated zero valent iron particles (for example,which appear as white colored relatively large irregularly shapedaggregates, as pointed to by the arrows) having an average size largerthan about 600 nm, without an electron transfer mediator, for serving asan exemplary reference zero valent metal composite when compared to theexemplary zero valent metal composite of the present invention whichappears in the SEM photographs of FIGS. 2A and 2B. Comparison of the SEMphotographs of FIGS. 2A and 2B with that of FIG. 3 clearly shows thesignificantly different geometrical shape or form of the zero valentiron particles, in particular, relatively small circularly shapedparticles (FIGS. 2A and 2B) vs. relatively large irregularly shapedaggregates (FIG. 3), according to the presence or absence, respectively,of an electron transfer mediator (for example, vitamin B₁₂) incorporatedon or/and in the powdered diatomite matrix of the zero valent ironcomposite.

These exemplary empirical observations based on comparisons of the SEMphotographs of FIGS. 2A and 2B with those of FIGS. 1A, 1B, and 3,convincingly support several main general inventive aspects of thepresent invention. Firstly, wherein the presence of an electron transfermediator (for example, vitamin B₁₂) incorporated on or/and in thepowdered diatomite matrix of the zero valent metal composite,significantly influences the geometrical shape or form of the zerovalent metal particles additionally incorporated on or/and in thepowdered diatomite matrix of the zero valent metal composite. Secondly,wherein the presence of an electron transfer mediator (for example,vitamin B₁₂) during the manufacturing (synthesizing) of the zero valentmetal composite, significantly influences the geometrical shape or formof the zero valent metal particles in the manufactured (synthesized)zero valent metal composite. Thirdly, wherein, apparently, the presenceof an electron transfer mediator (for example, vitamin B₁₂) incorporatedon or/and in the powdered diatomite matrix of the zero valent metalcomposite, significantly influences the physicochemical properties,characteristics, and behavior, of the zero valent metal particlesadditionally incorporated on or/and in the powdered diatomite matrix ofthe zero valent metal composite, in particular, and therefore, of thezero valent metal composite, in general. This includes, for example,with respect to applications involving the use of the zero valent metalcomposite for treating contaminated water.

In an alternative preferred embodiment of the present invention, thezero valent metal composite, as described hereinabove, optionally,additionally includes vermiculite. The vermiculite additionally includedin the zero valent metal composite originates from a piece, flake,sheet, or chip, form of the well known and readily availablevermiculite.

In such an alternative preferred embodiment of the present invention,the vermiculite additionally included in the zero valent metal compositeis, for example, in the form of pieces, flakes, sheets, or chips,herein, generally referred to as pieces, being of any combination ofvarious possible regular or/and irregular polygonal (for example,rectangular, square, hexagonal), elliptical, or spherical, shapes.Accordingly, the piece size, in terms of a ‘characteristic’ piece sizedimension, of the vermiculite additionally included in the zero valentmetal composite, on a dry basis, is in a range of between about 0.01 mmand about 20 mm. More preferably, the piece size of the vermiculite isin a range of between about 0.05 mm and about 10 mm, and mostpreferably, is in a range of between about 0.1 mm and about 5 mm. Takinginto account non-uniform or/and irregular geometrical shapes of thepieces, flakes, sheets, or chips, a characteristic piece size dimensionof the pieces of the vermiculite can be considered to be, for example,the longest distance (long distance) or longest diameter (long diameter)spanning across two ends of a piece, flake, sheet, or chip, of thevermiculite.

In such an alternative preferred embodiment of the present invention,the concentration, in terms of weight percent, of the vermiculiteadditionally included in the zero valent metal composite, on a drybasis, is in a range of between about 20% and about 95%. Morepreferably, the weight percent of the vermiculite is in a range ofbetween about 25% and about 75%, and most preferably, is in a range ofbetween about 35% and about 65%. As used herein, the concentration, interms of weight percent, of the vermiculite additionally included in thezero valent metal composite corresponds to the weight of the vermiculiteas a percent of the total weight of the zero valent metal composite(including the vermiculite), which can be written as (weight of thevermiculite/total weight of the zero valent metal composite)×100.

The hereinabove described and numerically valued structural propertiesand parameters, in particular, particle size, pore size, and weight(mass) percent, of the components of the zero valent metal composite,with respect to a ‘dry basis’, are useful for characterizing the zerovalent metal composite of the present invention. For additionallycharacterizing the zero valent metal composite, in particular, withrespect to applications of treating contaminated water, especially inthe form of ‘flowing’ contaminated sub-surface water, surface water, orabove-surface water, there is the physicochemical property or parameterof permeability, k, of the zero valent metal composite, which isevaluated from empirical or/and theoretical data and informationobtained from, or corresponding to, the zero valent metal composite, andcomponents thereof, being in a ‘wet’ (for example, water filled andflowing) environment.

As used herein, consistent with that known in the fields of fluiddynamics, hydraulics, and geology, the permeability, k, is an intrinsicphysicochemical property or parameter of a porous substance or materialthat quantifies the ability of the porous substance or material totransmit a fluid, for example, liquid phase water, through it, naturallyor forcibly, evaluated at specified operating and environmentalconditions (for example, temperature, pressure, natural/forced flow,absence or presence of surrounding materials which may influence thebulk packing and density of the porous substance or material), and hasdimensions of distance times distance (for example, cm²). Poroussubstances or materials (for example, diatomite, vermiculite) obtainedfrom natural (in particular, geologic) sources are typicallyheterogeneous, and the extent of heterogeneity of the porous substanceor material, in addition to being a function of operating andenvironmental conditions, is also a function of volume and mass scalesof measurement. Accordingly, the permeability, k, of such poroussubstances or materials corresponds to an ‘average’ physicochemicalproperty or parameter, relevant to the volume and mass scales ofmeasurement.

Regarding the permeability, k, of the zero valent metal composite,according to another main aspect of the present invention, to beillustratively described hereinbelow, there is provided a method forcatalytically treating contaminated water, including the step ofexposing the contaminated water to a catalytically effective amount ofthe hereinabove described zero valent metal composite, to therebydecrease concentration of at least one contaminant in the contaminatedwater. For implementing the method, a system (further describedhereinbelow and illustrated in FIGS. 4-8) can be used, which preferablyincludes any of the hereinabove previously described embodiments of thezero valent metal composite, and at least one (in-situ or/and ex-situ)unit for containing a catalytically effective amount of the zero valentmetal composite, for exposing the contaminated water to the zero valentmetal composite.

Exemplary applicable in-situ units for containing the zero valent metalcomposite are either in a form as at least part of a sub-surface waterpermeable reactive barrier (PRB) configured as a continuous filled intrench, wall, or stand-alone well, or, in a form as part of asub-surface water pumping and treatment system. An exemplary applicableex-situ unit for containing the zero valent metal composite is in a formas part of an above-surface reactor which is part of an above-surfacewater pumping and treatment system. For treating contaminated waterparticularly being a form of water vapor or/and gaseous water, anexemplary applicable in-situ or ex-situ unit for containing the zerovalent metal composite is in a form as part of a variably locatable(sub-surface or above-surface) water treatment reactor system.

Exposing contaminated water to the zero valent metal composite of thepresent invention can be performed according to any of a variety ofdifferent ways. For implementing the present invention, preferably, themanner of exposure is such that the contaminated water, for example, inthe form of contaminated sub-surface water, surface water, orabove-surface water, naturally or forcibly, flows through, and isbrought into physicochemical contact with, the zero valent metalcomposite while the zero valent metal composite remains essentiallystationary. Moreover, preferably, the manner of exposure is such thatthe volumetric or mass flow rate of the contaminated water, naturally orforcibly, flowing through the zero valent metal composite is at leastequal to or larger than the volumetric or mass flow rate of thecontaminated water, naturally or forcibly, flowing through the ground ormaterial immediately surrounding the zero valent metal composite.Accordingly, preferably, the manner of exposure is such that thepermeability, k, of the zero valent metal composite is at least equal toor larger than the permeability, k, of the ground or materialimmediately surrounding the zero valent metal composite. As describedhereinbelow and illustrated in FIGS. 4-8, such preferred ways ofexposure are applicable to an embodiment of the system of the presentinvention wherein the zero valent metal composite is contained in atleast one unit located in a flow path as part of an overall system usedfor processing or treating the contaminated water.

Thus, for additionally characterizing the zero valent metal composite ofthe present invention, the permeability, k, of the zero valent metalcomposite as described hereinabove (for the preferred embodiment withoutvermiculite, or for the alternative preferred embodiment whichadditionally includes vermiculite), in a ‘wet’ (for example, waterfilled and flowing) environment, is on the order of at least equal to orgreater than about 10⁻⁹ cm².

Following are selected details regarding the chemical bonding betweenthe components (powdered diatomite matrix, zero valent metal particles,electron transfer mediator, and, optionally, vermiculite) of the zerovalent metal composite of the present invention.

The nanometer sized particles (crystals) of the zero valent metalchemically adhere to the silica surface of the powdered diatomite matrixin an apparently covalent type of chemical bonding configuration.Apparently, the covalent type of chemical bonding configuration arisesas a result of formation of a covalent type of interface bond betweenthe zero valent metal particles and an oxide form of the powdereddiatomite matrix surface. This is supported by several well knownalternative mechanisms which are used for explaining and characterizingthe formation of covalent bonds between elemental (zero valent)transition metals and silica (silicon oxide) surfaces.

According to a first mechanism, the nature of interactions between anelemental (zero valent) transition metal and a silica (silicon oxide)surface is considered to drive the formation of covalent polar bonds viamixing of 3d orbitals of the metal with 2p orbitals of O bands of thesilicon oxide. According to a second mechanism, the nature ofinteractions is based on activation of the silica (silicon oxide)surface which drives covalent bonding of the metal via formation ofsiloxane links. According to a third mechanism, the nature ofinteractions is based on reaction of the metal with silica surfacesilanols freed from adsorbed water by cavitation, for forming positivelycharged metal on the silica surface, in the form of Si—O-M+ sites. TheseSi—O-M+ sites apparently serve as nucleating centers for the furtheragglomeration of the metal.

Electron transfer mediator molecules chemically adhere primarily to thesilica surface of the powdered diatomite matrix via covalent or/andother types of chemical bonding configurations, such as ionic,coordinative, or/and hydrogen bonding configurations. To some extent,electron transfer mediator molecules also chemically adhere to themetallic surface of the zero valent metal particles via covalent or/andother types of chemical bonding configurations, such as ionic,coordinative, or/and hydrogen bonding configurations. For thehereinabove described alternative preferred embodiment of the zerovalent metal composite which additionally includes vermiculite, electrontransfer mediator molecules may also chemically adhere to the hydratedsilicate surface of the vermiculite via covalent or/and other types ofchemical bonding configurations, such as ionic, coordinative, or/andhydrogen bonding configurations, or/and may also physically adhere tothe hydrated silicate surface of the vermiculite via various types ofphysical bonding configurations.

Following are selected details regarding the functions of the components(powdered diatomite matrix, zero valent metal particles, electrontransfer mediator, and, optionally, vermiculite) of the zero valentmetal composite of the present invention.

The powdered diatomite matrix primarily functions as a physicochemicalmatrix, or support, for the catalytically active zero valent metalparticles and the at least one electron transfer mediator. Morespecifically, the surface or/and pores of the powdered diatomite matrixprimarily function as hosts for the dispersion, support, entrapment andadherence, in a chemical or/and physical bonding manner, of the zerovalent metal particles and the at least one electron mediator which areincorporated on or/and in the powdered diatomite matrix.

The zero valent metal particles primarily function as a bulk electrondonor or reducing agent (which becomes oxidized) during occurrence ofthe redox (reduction-oxidation) reactions which take place duringexposure of contaminated water to a catalytically effective amount ofthe zero valent metal composite, to thereby decrease concentration of atleast one contaminant in the contaminated water. Inclusion of the zerovalent metal particles (functioning as a bulk electron donor or reducingagent) in the zero valent metal composite provides for, and enables, thevarious heterogeneous catalytic reaction processes to take place underreducing (anaerobic or anoxic) conditions within the contaminated water,for heterogeneously catalytically treating the contaminated water, tothereby decrease the concentration of at least one of the chemicalcontaminants in the contaminated water. Accordingly, exposure ofcontaminated water to a catalytically effective amount of the zerovalent metal composite takes place under reducing (anaerobic or anoxic)conditions, i.e., as opposed to oxidizing conditions.

As stated hereinabove, an ‘electron transfer mediator’ is a chemicalsubstance, functioning as a catalyst or co-catalyst, which iscatalytically active, and expedites (catalyzes) redox(reduction-oxidation) types of chemical reactions, such as reductivedehalogenation, by participating in, mediating, and expediting, thetransfer of electrons from a bulk electron donor or reducing agent to anelectron acceptor, or/and by stabilizing intermediate forms of the redoxreactants. An electron transfer mediator which specifically functions byparticipating in, mediating, and expediting, the transfer of electronsfrom an electron donor or reducing agent to an electron acceptor is alsoknown as an electron carrier or as an electron shuttle, since electronsare carried and shuttled by such a chemical species.

Accordingly, each electron transfer mediator which is/are incorporatedon or/and in the powdered diatomite matrix of the zero valent metalcomposite of the present invention primarily functions as a chemicalsubstance which is catalytically active. Moreover, each electrontransfer mediator facilitates at least one redox (reduction-oxidation)reaction, for example, taking place between contaminants in contaminatedwater and the zero valent metal composite of the present invention, bymediating, and participating in, the transfer of electrons between anelectron donor, for example, a catalyst, such as the zero valent metalparticles in the composite of the present invention, and an electronacceptor, for example, a water contaminant, such as a halogenatedorganic compound, or/and by stabilizing an intermediate form of a redoxreactant. An electron transfer mediator which specifically functions bymediating, and participating in, the transfer of electrons between anelectron donor, such as the zero valent metal particles in the compositeof the present invention, and an electron acceptor, for example, a watercontaminant, such as a halogenated organic compound, therefore,specifically functions as an electron carrier or as an electron shuttle.

The vermiculite primarily functions as a physical scaffold, being aframe or platform, for physically supporting the powdered diatomitematrix on or/and in which are incorporated the zero valent metalparticles and the at least one electron mediator. The vermiculite mayalso function by increasing the adsorption, in addition to the porosityand permeability (permeability, k), properties, parameters,characteristics, and behavior, of the zero valent metal composite. Thevermiculite may also function as a chemically active species, forexample, by serving as an additional support for chemisorption ofreaction species, participating in the redox (reduction-oxidation)reaction(s) taking place between contaminants in contaminated water andthe zero valent metal composite of the present invention, during thecatalytic treatment of the contaminated water.

The components (powdered diatomite matrix, zero valent metal particles,electron transfer mediator, and, optionally, vermiculite) of the zerovalent metal composite, when present in a catalytically effectiveamount, and exposed to contaminated water, singly, or in a synergisticcombination, catalytically decrease concentration of at least onecontaminant in the contaminated water.

According to another main aspect of the present invention, there isprovision of a method for manufacturing a zero valent metal composite,which is effected by incorporating zero valent metal particles having asize in a range of between about 1 nm and about 1000 nm and at least oneelectron transfer mediator on or/and in a powdered diatomite matrix.

There is a wide variety of different possible procedures, steps andsub-steps, alternative steps and sub-steps, optional steps andsub-steps, and, orders or sequences thereof, for implementing the methodfor manufacturing a zero valent metal composite, in accordance with thepresent invention. Moreover, actual procedures, steps and sub-steps,alternative steps and sub-steps, optional steps and sub-steps, and,orders or sequences thereof, which are used for implementing the methodfor manufacturing a zero valent metal composite, in accordance with thepresent invention, are performed according to the actual type and sizescale (e.g., laboratory, pilot-plant, commercial), of implementation.

For the objective of illustrating implementation of the presentinvention, in a non-limiting manner, there is described hereinbelow, anexemplary preferred embodiment of the method for manufacturing the zerovalent metal composite of the present invention, wherein the procedureof incorporating the zero valent metal particles having a size in arange of between about 1 nm and about 1000 nm and the electron transfermediator(s) on or/and in a powdered diatomite matrix, is performed bythe following exemplary order or sequence of procedures (a)-(i):

(a) preparing an aqueous solution of a metal salt; (b) preparing anaqueous solution of the electron transfer mediator(s); (c) adding theaqueous solution of the electron transfer mediator(s) to the aqueoussolution of the metal salt, for forming an aqueous solution of the metalsalt and the electron transfer mediator(s); (d) adding the powdereddiatomite matrix to the aqueous solution of the metal salt and theelectron transfer mediator(s), for forming an aqueous slurry of themetal salt, the electron transfer mediator(s), and the powdereddiatomite matrix; (e) preparing an aqueous solution of a strong reducingagent; (f) forming and initiating reaction of a redox reaction mixtureof the aqueous slurry of the metal salt, the electron transfermediator(s), and the powdered diatomite matrix, with the aqueoussolution of the strong reducing agent; (g) allowing the redox reactionmixture to react to completion, for forming a product mixture of thezero valent metal composite in water; (h) collecting the zero valentmetal composite; and (i) drying the collected zero valent metalcomposite, for forming dry zero valent metal composite.

Immediately following are details of each of the above indicatedprocedures (a)-(i), as part of the exemplary preferred embodiment of themethod for manufacturing the zero valent metal composite of the presentinvention.

In (a), there is preparing an aqueous solution of a metal salt.

For performing this procedure, there is dissolving a metal salt inwater, for forming the aqueous solution of the metal salt. The aqueoussolution of the metal salt is placed in a filter flask in an anaerobicchamber.

Preferably, the metal salt used for preparing the aqueous solution ofthe metal salt is selected from the group consisting of transition metalsalts. More preferably, the transition metal salt is selected from thegroup consisting of iron salts, cobalt salts, nickel salts, coppersalts, zinc salts, palladium salts, platinum salts, gold salts, or anycombination thereof. Most preferably, the transition metal salt is aniron salt.

In a non-limiting manner, selected specific examples of each of thesetypes of exemplary transition metal salts, which are applicable forperforming this procedure of preparing an aqueous solution of a metalsalt, are provided immediately hereinbelow. Herein, consistent withstandard chemical nomenclature and terminology, with respect to thehydrate forms of any of the below listed transition metal salts, theterm ‘n’ represents a real, but not necessarily whole, number, such as0.5 (semi-hydrate), 1.0 (monohydrate), 1.5, 2 (dihydrate), 3(trihydrate), 4 (tetrahydrate), 5 (pentahydrate), 6 (hyxahydrate), 7(heptahydrate), 8 (octahydrate), . . . , etc.

An exemplary iron salt is selected from the group consisting of ironalkali salts, iron sulfate salts, iron nitrate salts, and iron phosphatesalts. An exemplary iron alkali salt is selected from the groupconsisting of iron chloride salts, iron bromide salts, and iron iodidesalts. An exemplary iron chloride salt is selected from the groupconsisting of iron(III) chloride hexahydrate [FeCl₃.6H₂O], iron(II)chloride [FeCl₂], and iron(II) chloride tetrahydrate [FeCl₂.4H₂O]. Anexemplary iron bromide salt is selected from the group consisting ofiron(II) bromide [FeBr₂], and iron(III) bromide [FeBr₃]. An exemplaryiron iodide salt is selected from the group consisting of iron(II)iodide [FeI₂], and iron(II) iodide tetrahyrate [FeI₂.4H₂O]. An exemplaryiron sulfate salt is selected from the group consisting of iron sulfatehydrates [FeSO₄.nH₂O], such as iron sulfate heptahyrate [FeSO₄.7H₂O]. Anexemplary iron nitrate salt is iron nitrate nonahydrate [Fe(NO₃)₃.9H₂O].An exemplary iron phosphate salt is iron(III) phosphate tetrahydrate[FePO₄.4H₂O].

An exemplary cobalt salt is selected from the group consisting of cobaltalkali salts, cobalt sulfate salts, cobalt nitrate salts, and cobaltphosphate salts. An exemplary cobalt alkali salt is selected from thegroup consisting of cobalt chloride salts, cobalt bromide salts, andcobalt iodide salts. An exemplary cobalt chloride salt is selected fromthe group consisting of cobalt(II) chloride [CoCl₂], and cobalt(II)chloride hydrates [CoCl₂.nH₂O], such as cobalt(II) chloride hexahydrate[CoCl₂.6H₂O]. An exemplary cobalt bromide salt is selected from thegroup consisting of cobalt(II) bromide [CoBr₂], and cobalt(II) bromidehydrates [CoBr₂.nH₂O]. An exemplary cobalt iodide salt is cobalt(II)iodide [CoI₂]. An exemplary cobalt sulfate salt is selected from thegroup consisting of cobalt(II) sulfate hydrates [CoSO₄.nH₂O], such ascobalt(II) sulfate heptahydrate [CoSO₄.7H₂O]. An exemplary cobaltnitrate salt is cobalt(II) nitrate hexahydrate [Co(NO₃)₂.6H₂O]. Anexemplary cobalt phosphate salt is selected from the group consisting ofcobalt(II) phosphate hydrates [Co(PO₄)₂.nH₂O].

An exemplary nickel salt is selected from the group consisting of nickelalkali salts, nickel sulfate salts, and nickel nitrate salts. Anexemplary nickel alkali salt is selected from the group consisting ofnickel chloride salts, nickel bromide salts, and nickel iodide salts. Anexemplary nickel chloride salt is selected from the group consisting ofnickel(II) chloride [NiCl₂], and nickel(II) chloride hydrates[NiCl₂.nH₂O], such as nickel(II) chloride hexahydrate [NiCl₂.6H₂O]. Anexemplary nickel bromide salt is selected from the group consisting ofnickel(II) bromide [NiBr₂], and nickel(II) bromide hydrates[NiBr₂.nH₂O], such as nickel(II) bromide trihydrate [NiBr₂.3H₂O]. Anexemplary nickel iodide salt is nickel(II) iodide [NiI₂]. An exemplarynickel sulfate salt is selected from the group consisting of nickel(II)sulfate hexahydrate [NiSO₄.6H₂O], and nickel(II) sulfate heptahydrate[NiSO₄.7H₂O].

An exemplary nickel nitrate salt is nickel(II) nitrate hexahydrate[Ni(NO₃)₂.6H₂O].

An exemplary copper salt is selected from the group consisting of copperalkali salts, copper sulfate salts, copper nitrate salts, and copperphosphate salts. An exemplary copper alkali salt is selected from thegroup consisting of copper chloride salts, copper bromide salts, andcopper iodide salts. An exemplary copper chloride salt is selected fromthe group consisting of copper(II) chloride [CuCl₂], and copper(II)chloride dihydrate [CuCl₂.2H₂O]. An exemplary copper bromide salt iscopper(II) bromide [CuBr₂]. An exemplary copper iodide salt iscopper(II) iodide [CuI₂]. An exemplary copper sulfate salt is selectedfrom the group consisting of copper(II) sulfate [CuSO₄], and copper(II)sulfate hydrates [CuSO₄.nH₂O], such as copper(II) sulfate pentahydrate[CuSO₄.5H₂O]. An exemplary copper nitrate salt is selected from thegroup consisting of copper(II) nitrate trihydrate [Cu(NO₃)₂.3H₂O], andcopper(II) nitrate hexahydrate [Cu(NO₃)₂.6H₂O]. An exemplary copperphosphate salt is copper(II) phosphate dihydrate [Cu₃(PO₄)₂.2H₂O].

An exemplary zinc salt is selected from the group consisting of zincalkali salts, zinc sulfate salts, and zinc nitrate salts. An exemplaryzinc alkali salt is selected from the group consisting of zinc chloridesalts, zinc bromide salts, and zinc iodide salts. An exemplary zincchloride salt is zinc chloride [ZnCl₂]. An exemplary zinc bromide saltis selected from the group consisting of zinc bromide [ZnBr₂], and zincbromide dihydrate [ZnBr₂.2H₂O]. An exemplary zinc iodide salt is zinciodide [ZnI₂]. An exemplary zinc sulfate salt is selected from the groupconsisting of zinc sulfate monohydrate [ZnSO₄.H₂O], and zinc sulfateheptahydrate [ZnSO₄.7H₂O]. An exemplary zinc nitrate salt is selectedfrom the group consisting of zinc nitrate hydrates [Zn(NO₃)₂.nH₂O], suchas zinc nitrate hexahydrate [Zn(NO₃)₂.6H₂O].

An exemplary palladium salt is selected from the group consisting ofpalladium alkali salts, palladium sulfate salts, palladium nitratesalts, and palladium cyanide salts. An exemplary palladium alkali saltis selected from the group consisting of palladium chloride salts,palladium bromide salts, palladium fluoride, and palladium iodide salts.An exemplary palladium chloride salt is selected from the groupconsisting of palladium chloride [PdCl₂], and palladium chloridedihydrate [PdCl₂.2H₂O]. An exemplary palladium bromide salt is palladiumbromide [PdBr₂]. An exemplary palladium fluoride salt is selected fromthe group consisting of palladium difluoride [PdF₂], and palladiumtrifluoride [PdF₃]. An exemplary palladium iodide salt is palladiumiodide [PdI₂]. An exemplary palladium sulfate salt is palladium sulfatedihydrate [PdSO₄.2H₂O]. An exemplary palladium sulfide salt is selectedfrom the group consisting of palladium monosulfide [PdS], palladiumdisulfide [PdS₂], and palladium subsulfide [Pd₂S]. An exemplarypalladium nitrate salt is palladium nitrate [Pd(NO₃)₂]. An exemplarypalladium cyanide salt is palladium cyanide [Pd(CN)₂].

An exemplary platinum salt is selected from the group consisting ofplatinum alkali salts, platinum sulfate salts, platinum sulfide salts,and platinum cyanide salts. An exemplary platinum alkali salt isselected from the group consisting of platinum chloride salts, platinumbromide salts, platinum fluoride, and platinum iodide salts. Anexemplary platinum chloride salt is selected from the group consistingof platinum dichloride [PtCl₂], platinum tetrachloride [PtCl₄], platinumtrichloride [PtCl₃], and platinum tetrachloride pentahydrate[PtCl₄.5H₂O]. An exemplary platinum bromide salt is selected from thegroup consisting of platinum dibromide [PtBr₂], and platinumtetrabromide [PdBr₄]. An exemplary platinum fluoride salt is selectedfrom the group consisting of platinum difluoride [PtF₂], and platinumtetrafluoride [PdF₄]. An exemplary platinum iodide salt is selected fromthe group consisting of platinum iodide [PtI₂], and platinum tetraiodide[PtI₄]. An exemplary platinum sulfate salt is platinum sulfatetetrahydrate [Pt(SO₄)₂.4H₂O]. An exemplary platinum sulfide salt isselected from the group consisting of platinum monosulfide [PtS], andplatinum (II) disulfide [PtS₂]. An exemplary platinum cyanide salt isplatinum cyanide [Pt(CN)₂].

An exemplary gold salt is selected from the group consisting of goldalkali salts, gold sulfide salts, and gold cyanide salts. An exemplarygold alkali salt is selected from the group consisting of gold chloridesalts, gold bromide salts, and gold iodide salts. An exemplary goldchloride salt is selected from the group consisting of gold chloride[AuCl], and gold trichloride [AuCl₃] or [Au₂Cl₆]. An exemplary goldbromide salt is selected from the group consisting of gold bromide[AuBr], and gold tribromide [AuBr₃]. An exemplary gold iodide salt isselected from the group consisting of gold iodide [AuI], and goldtriiodide [AuI₃]. An exemplary gold sulfide salt is selected from thegroup consisting of gold sulfide [Au₂S], and digold trisulfide [Au₂S₃].An exemplary gold cyanide salt is gold cyanide [AuCN].

In (b), there is preparing an aqueous solution of the electron transfermediator(s).

Preferably, there is preparing a single aqueous solution of the electrontransfer mediator(s). For example, for the case of incorporating asingle electron transfer mediator on or/and in the powdered diatomitematrix of the zero valent metal composite, there is preparing a singleaqueous solution of the single electron transfer mediator. For the caseof incorporating at least two electron transfer mediators on or/and inthe powdered diatomite matrix of the zero valent metal composite, thereis preparing a single aqueous solution of all of the at least twoelectron transfer mediators. Alternatively, there is separatelypreparing a single aqueous solution of each of the at least two electrontransfer mediators.

Preferably, the at least one electron transfer mediator which is/areused for preparing the aqueous solution of the at least one electrontransfer mediator, is selected from the group of porphyrinogenicorganometallic complexes, analogs thereof, and derivatives thereof, asdefined and detailed hereinabove.

In (c), there is adding the aqueous solution of the at least oneelectron transfer mediator to the aqueous solution of the metal salt,for forming an aqueous solution of the metal salt and the at least oneelectron transfer mediator.

For performing this procedure, the aqueous solution of the at least oneelectron transfer mediator is poured into the aqueous solution of themetal salt, and then the combined solution is mixed to yield ahomogeneous aqueous solution of the metal salt and the at least oneelectron transfer mediator.

In (d), there is adding the powdered diatomite matrix, being a powderedform of diatomite (kieselguhr), to the aqueous solution of the metalsalt and the electron transfer mediator(s), for forming an aqueousslurry of the metal salt, the electron transfer mediator(s), and thepowdered diatomite matrix.

For performing this procedure, typically, additional water is added tothe aqueous slurry which is initially formed upon commencing addition ofthe powdered diatomite matrix. Preferably, the aqueous slurry of themetal salt, the electron transfer mediator(s), and the powdereddiatomite matrix, is of a consistency which can be mixed by stirring,for example, magnetic stirring, or some other type of preferably,automated, stirring mechanism or device, according to the actual typeand size scale (e.g., laboratory, pilot-plant, commercial), required forimplementing the overall method for manufacturing (synthesizing) thezero valent metal composite, in accordance with the present invention.The aqueous slurry is then placed in a fume hood, or some other type offume ventilating assembly, and mixed by stirring, for example, magneticstirring.

As previously stated hereinabove in the description of the preferredembodiments of the zero valent metal composite of the present invention,the powdered diatomite matrix included in the zero valent metalcomposite originates from a powdered form of the well known and readilyavailable diatomite (diatomaceous earth or kieselguhr), being a porous,chalk-like, sedimentary rock, formed by fossil accumulation of diatomsin the form of amorphous, hydrated silica. The powdered diatomite makingup the powdered diatomite matrix of the zero valent metal composite ofthe present invention, and used in the method for manufacturing the zerovalent metal composite, in accordance with the present invention, isreadily obtained from a commercial source of powdered diatomite, in an‘as is’ form having any of the hereinabove previously indicated averageparticle size and pore size ranges. Alternatively, the powdereddiatomite is readily obtained from a commercial source of non-powdereddiatomite, in an ‘as is’ form having any of the above indicated averagepore size ranges, but having a larger than desired average particle sizerange, whereby the non-powdered diatomite is then readily crushed or/andphysically processed into a powdered form, and sieved into the desiredaverage particle size range according to a particular application.

In (e), there is preparing an aqueous solution of a strong reducingagent.

The aqueous solution of the strong reducing agent is either prepared in,or transferred to, an appropriately sized low light transmittingcontainer (for example, an opaque brown (or amber) glass container(e.g., an amber bottle)), preferably unexposed to sunlight, which isthen placed in an anaerobic chamber.

Preferably, the strong reducing agent used for preparing the aqueoussolution of the strong reducing agent is selected from the groupconsisting of hydride types of reducing reagents, dihydrogen types ofreducing reagents, metallic types of reducing reagents, andorganometallic types of reducing reagents.

Examples of such reducing reagents are alkali borohydrides, such assodium borohydride (NaBH₄), or other alkali borohydrides, for example,cyano derivatives of sodium borohydride (NaBH₄), such as NaBH₃CN.

In (f), there is forming and initiating reaction of a redox reactionmixture of the aqueous slurry of the metal salt, the electron transfermediator(s), and the powdered diatomite matrix, with the aqueoussolution of the strong reducing agent.

The aqueous slurry of the metal salt, the electron transfer mediator(s),and the powdered diatomite matrix, of (d), and the aqueous solution ofthe strong reducing agent of (e), are each placed in a reaction vessel,which is magnetically stirred in a fume hood. Forming and initiatingreaction of the redox reaction mixture are performed, for example, bypumping and drop-wise adding the aqueous solution of the strong reducingagent to the reaction vessel containing the aqueous slurry of the metalsalt, the at least one electron transfer mediator, and the powdereddiatomite matrix, while mixing, and supplying an inert gas to thereaction vessel for preventing intrusion of oxygen. Preferred exemplaryinert gases suitable for performing this step are nitrogen, argon, or acombination thereof.

In (g), there is allowing the redox reaction mixture to react tocompletion, for forming a product mixture of the zero valent metalcomposite in water.

The redox reaction mixture reacts to completion upon delivering thenecessary amount of the strong reducing agent to the reaction vesselcontaining the aqueous slurry.

During reaction among the reactants (the metal salt, the at least oneelectron transfer mediator, the powdered diatomite matrix, and thestrong reducing agent) of the redox reaction mixture, being mixed in anaqueous environment, the oxidized form of the metal in the metal salt isreduced to the zero valent metal, which in turn precipitates onto thesilica surface or/and in the silica pores of the powdered diatomitematrix.

As previously stated hereinabove, nanometer sized particles (crystals)of the zero valent metal chemically adhere to the silica surface or/andpores of the powdered diatomite matrix in a covalent type of chemicalbonding configuration. Apparently, the covalent type of chemical bondingconfiguration arises as a result of formation of a covalent type ofinterface bond between the zero valent metal particles and an oxide formof the powdered diatomite matrix surface. This is supported by severalwell known alternative mechanisms, briefly described hereinabove, whichare used for explaining and characterizing the formation of covalentbonds between elemental (zero valent) transition metals and silica(silicon oxide) surfaces.

Electron transfer mediator molecules chemically adhere primarily to thesilica surface or/and pores of the powdered diatomite matrix viacovalent or/and other types of chemical bonding configurations, such asionic, coordinative, or/and hydrogen bonding configurations. To someextent, electron transfer mediator molecules also chemically adhere tothe metallic surface of the zero valent metal particles via covalentor/and other types of chemical bonding configurations, such as ionic,coordinative, or/and hydrogen bonding configurations.

During the reaction taking place in (g) for forming the zero valentmetal composite, the electron transfer mediator may function as achemically active species, for example, by actively facilitating(mediating, catalyzing, or co-catalyzing) the reduction of the oxidizedform of the metal in the metal salt to the zero valent metal, or/and byactively facilitating (mediating, catalyzing, or co-catalyzing) thebonding of the zero valent metal to the silica surface of the powdereddiatomite matrix.

When the redox reaction mixture has completed reacting, the zero valentmetal composite formed as part of the product mixture is composed of thepowdered diatomite matrix on or/and in which is incorporated zero thevalent metal particles having the size in the range of between about 1nm and about 1000 nm and the at least one electron transfer mediator.

In (h), there is collecting the zero valent metal composite.

This procedure is performed, for example, by transferring the zerovalent metal composite to an anaerobic chamber, filtering, and thenwashing the zero valent metal composite with water and a suitableorganic solvent, such as acetone.

In (i), there is drying the collected zero valent metal composite, forforming dry zero valent metal composite.

This procedure is performed, for example, by drying the collected zerovalent metal composite in the anaerobic chamber, by using vacuumpumping. Following the drying procedure, the dry zero valent metalcomposite is stored in a closed container in the anaerobic chamber untilneeded for use.

Example 1, hereinbelow in the Examples section, describes an actualexample of implementing the just described exemplary preferredembodiment of the method for manufacturing a zero valent metalcomposite, of the present invention, wherein the zero valent metalcomposite is a zero valent iron composite composed of a powdereddiatomite matrix on or/and in which is incorporated zero valent ironparticles having a size in a range of between about 1 nm and about 1000nm and vitamin B₁₂.

The immediately preceding description of the exemplary preferredembodiment of the method for manufacturing the zero valent metalcomposite of the present invention, including the procedure (a)-(i), isreadily implemented for manufacturing the hereinabove previouslydescribed zero valent metal composite composed of the powdered diatomitematrix on or/and in which is incorporated the zero valent metalparticles having the size in the range of between about 1 nm and about1000 nm and the at least one electron transfer mediator, andalternatively, is readily implemented for manufacturing the hereinabovepreviously described zero valent metal composite composed of thecomposition consisting essentially of the powdered diatomite matrix onor/and in which is incorporated the zero valent metal particles havingthe size in the range of between about 1 nm and about 1000 nm and the atleast one electron transfer mediator.

The immediately preceding description of the exemplary preferredembodiment of the method for manufacturing the zero valent metalcomposite of the present invention, optionally, further includes thestep of adding vermiculite. With inclusion of this additional step, theimmediately preceding description of the exemplary preferred embodimentof the method for manufacturing the zero valent metal composite of thepresent invention, is readily implemented for manufacturing thehereinabove previously described zero valent metal composite composed ofthe powdered diatomite matrix on or/and in which is incorporated zerovalent metal particles having the size in the range of between about 1nm and about 1000 nm and the at least one electron transfer mediator,and includes vermiculite.

In a first exemplary alternative preferred embodiment of themanufacturing method, the step of adding vermiculite is included as aprocedure, for example, as (a′), following (a) of preparing an aqueoussolution of a metal salt, and before (b) of preparing an aqueoussolution of the at least one electron transfer mediator. Accordingly, afirst exemplary alternative preferred embodiment of the method formanufacturing the zero valent metal composite of the present invention,wherein the step of incorporating zero valent metal particles having asize in a range of between about 1 nm and about 1000 nm and at least oneelectron transfer mediator on or/and in a powdered diatomite matrix,includes the following order or sequence of procedures (a)-(i):

(a) preparing an aqueous solution of a metal salt; (a′) addingvermiculite to the aqueous solution of the metal salt, for forming amixture of the vermiculite and the aqueous solution of the metal salt;(b) preparing an aqueous solution of the at least one electron transfermediator; (c) adding the aqueous solution of the at least one electrontransfer mediator to the mixture of the vermiculite and the aqueoussolution of the metal salt, for forming a mixture of the vermiculite andan aqueous solution of the metal salt and the at least one electrontransfer mediator; (d) adding the powdered diatomite matrix to themixture of the vermiculite and the aqueous solution of the metal saltand the at least one electron transfer mediator, for forming a mixtureof the vermiculite and an aqueous slurry of the metal salt, the at leastone electron transfer mediator, and the powdered diatomite matrix; (e)preparing an aqueous solution of a strong reducing agent; (f) formingand initiating reaction of a redox reaction mixture of the vermiculiteand the aqueous slurry of the metal salt, the at least one electrontransfer mediator, and the powdered diatomite matrix, with the aqueoussolution of the strong reducing agent; (g) allowing the redox reactionmixture to react to completion, for forming a product mixture of thezero valent metal composite (including vermiculite) in water; (h)collecting the zero valent metal composite (including vermiculite); and(i) drying the collected zero valent metal composite (includingvermiculite), for forming dry zero valent metal composite (includingvermiculite).

In the immediately preceding first exemplary alternative preferredembodiment of the method for manufacturing the zero valent metalcomposite of the present invention, procedures (a), (b), and (e), areidentical to the corresponding procedures (a), (b), and (e),respectively, of the hereinabove previously described exemplarypreferred embodiment of the method for manufacturing the zero valentmetal composite of the present invention. Procedure (a′) of addingvermiculite to the aqueous solution of the metal salt, for forming amixture of the vermiculite and the aqueous solution of the metal salt,has been inserted between (a) and (b) in the previous sequence ofprocedures (a)-(i). Procedures (c), (d), and (f), are similar to thecorresponding procedures (c), (d), and (f), respectively, in theprevious sequence of procedures (a)-(i), except for the explicitlystated additional presence of the vermiculite. Procedures (g), (h), and(i), are similar to the corresponding procedures (g), (h), and (i),respectively, in the previous sequence of procedures (a)-(i), except forthe implicitly understood and indicated additional presence of thevermiculite as part of the zero valent metal composite.

Example 2, hereinbelow in the Examples section, describes an actualexample of implementing the just described first exemplary alternativepreferred embodiment of the manufacturing method (optional addition ofvermiculite), of the present invention, wherein the zero valent metalcomposite is a zero valent iron composite composed of a powdereddiatomite matrix on or/and in which is incorporated zero valent ironparticles having a size in a range of between about 1 nm and about 1000nm and vitamin B₁₂, and includes vermiculite.

In a second exemplary alternative preferred embodiment of themanufacturing method, the step of adding vermiculite is included as aprocedure, for example, as procedure (h′), following procedure (h) ofcollecting the zero valent metal composite, and before procedure (i) ofdrying the collected zero valent metal composite. Accordingly, a secondexemplary alternative preferred embodiment of the method formanufacturing the zero valent metal composite of the present invention,wherein the procedure of incorporating zero valent metal particleshaving a size in a range of between about 1 nm and about 1000 nm and atleast one electron transfer mediator on or/and in a powdered diatomitematrix, includes the following order or sequence of procedures (a)-(i):

(a) preparing an aqueous solution of a metal salt; (b) preparing anaqueous solution of the at least one electron transfer mediator; (c)adding the aqueous solution of the at least one electron transfermediator to the aqueous solution of the metal salt, for forming anaqueous solution of the metal salt and the at least one electrontransfer mediator; (d) adding the powdered diatomite matrix to theaqueous solution of the metal salt and the at least one electrontransfer mediator, for forming an aqueous slurry of the metal salt, theat least one electron transfer mediator, and the powdered diatomitematrix; (e) preparing an aqueous solution of a strong reducing agent;(f) forming and initiating reaction of a redox reaction mixture of theaqueous slurry of the metal salt, the at least one electron transfermediator, and the powdered diatomite matrix, with the aqueous solutionof the strong reducing agent; (g) allowing the redox reaction mixture toreact to completion, for forming a product mixture of the zero valentmetal composite (absent of vermiculite) in water; (h) collecting thezero valent metal composite (absent of vermiculite); (h′) addingvermiculite to the collected zero valent metal composite (absent ofvermiculite), for forming the zero valent metal composite (includingvermiculite); and (i) drying the zero valent metal composite (includingvermiculite), for forming dry zero valent metal composite (includingvermiculite).

In the immediately preceding second exemplary alternative preferredembodiment of the method for manufacturing the zero valent metalcomposite of the present invention, procedures (a)-(h) are identical tothe corresponding procedures (a)-(h), respectively, of the hereinabovepreviously described exemplary preferred embodiment of the method formanufacturing the zero valent metal composite of the present invention.Procedure (h′) of adding vermiculite to the collected zero valent metalcomposite (absent of vermiculite), for forming the zero valent metalcomposite (including vermiculite), has been inserted between procedures(h) and (i) in the previous sequence of procedures (a)-(i). Preferably,procedure (h′) further includes washing the zero valent metal composite(including vermiculite) with water and a suitable organic solvent, suchas acetone, in an anaerobic chamber. Procedure (i) is similar to thecorresponding procedure (i) in the previous sequence of procedures(a)-(i), except for the indicated additional presence of the vermiculiteas part of the zero valent metal composite.

Example 3, hereinbelow in the Examples section, describes an actualexample of implementing the just described second exemplary alternativepreferred embodiment of the manufacturing method (optional addition ofvermiculite), of the present invention, wherein the zero valent metalcomposite is a zero valent iron composite composed of a powdereddiatomite matrix on or/and in which is incorporated zero valent ironparticles having a size in a range of between about 1 nm and about 1000nm and vitamin B₁₂, and includes vermiculite.

Following are selected additional details regarding the hereinabovedescribed exemplary preferred embodiment of the method for manufacturingthe zero valent metal composite of the present invention, whichoptionally, further includes the step of adding vermiculite, inaccordance with the just described first or second exemplary alternativepreferred embodiments thereof.

The vermiculite additionally included in the method for manufacturingthe zero valent metal composite originates from a piece, flake, or chip,form of the well known and readily available vermiculite.

In the just described first exemplary alternative preferred embodimentof the manufacturing method, during the reaction taking place in (g) forforming the zero valent metal composite (including vermiculite), inaddition to the electron transfer mediator, the vermiculite may alsofunction as a chemically active species, for example, by activelyfacilitating (mediating, catalyzing, or co-catalyzing) the reduction ofthe oxidized form of the metal in the metal salt to the zero valentmetal, or/and by actively facilitating (mediating, catalyzing, orco-catalyzing) the bonding of the zero valent metal to the silicasurface of the powdered diatomite matrix.

Additionally, in the just described first exemplary alternativepreferred embodiment of the manufacturing method, as previously statedhereinabove, for the hereinabove described alternative preferredembodiment of the zero valent metal composite which additionallyincludes vermiculite, electron transfer mediator molecules may alsochemically adhere to the hydrated silicate surface of the vermiculitevia covalent or/and other types of chemical bonding configurations, suchas ionic, coordinative, or/and hydrogen bonding configurations, or/andmay also physically adhere to the hydrated silicate surface of thevermiculite via various types of physical bonding configurations.

According to another main aspect of the present invention, there isprovision of a method for catalytically treating contaminated water,including the procedure of exposing the contaminated water to acatalytically effective amount of a zero valent metal composite composedof a powdered diatomite matrix on or/and in which is incorporated zerovalent metal particles having a size in a range of between about 1 nmand about 1000 nm and at least one electron transfer mediator, tothereby decrease concentration of at least one contaminant in thecontaminated water.

The method for catalytically treating contaminated water, of the presentinvention, is a heterogeneous catalytic chemical technique for treatingcontaminated water which is based on exploiting ‘heterogeneous catalyticchemical reaction’ types of mechanisms, processes, and phenomena,involving the use of one or more chemicals functioning as a catalyst for‘catalytically’ transforming, converting, or degrading, the contaminantsin the contaminated water to non-toxic or/and less toxic species.

As used herein, a ‘catalytically effective amount of the zero valentmetal composite’ means the amount (for example, in terms of mass,weight, or volume) of the zero valent metal composite that catalyticallydecreases concentration of at least one contaminant in a given amount ofcontaminated water. The actual catalytically effective amount of thezero valent metal composite needed to practice the invention dependsupon several parameters of a given system.

Primary parameters are the types, quantities, concentrations, and,physicochemical and hydrodynamic (flow) properties, characteristics, andbehavior, of the contaminated water, of the individual contaminants inthe water, and of the zero valent metal composite, throughout thecatalytic reaction zone or region. Secondary parameters are thetemperatures and pressures, and possible gradients thereof, of thecontaminated water, of the individual contaminants in the water, and ofthe zero valent metal composite, within the catalytic reaction zone orregion. Tertiary parameters correspond to the just indicated primary andsecondary parameters, but with respect to other material(s) possiblypresent throughout, or/and in the immediate vicinity surrounding, thecatalytic reaction zone or region.

The method for catalytically treating contaminated water is readilyimplemented by using any of the hereinabove previously describedembodiments of the zero valent metal composite of the present invention.In particular, a zero valent metal composite composed of a powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having a size in a range of between about 1 nm and about 1000nm and at least one electron transfer mediator, or, alternatively, whichadditionally includes vermiculite.

Accordingly, the zero valent metal used for implementing the method forcatalytically treating contaminated water has the hereinabove previouslydescribed and numerically valued structural properties and parameters,in particular, particle size, pore size, and weight (mass) percent, ofthe components (powdered diatomite matrix, nanometer sized zero valentmetal particles, at least one electron transfer mediator, and,optionally, vermiculite) of the zero valent metal composite, and has thehereinabove previously described and numerically valued physicochemicalproperty or parameter of permeability, k. Moreover, the zero valentmetal used for implementing the method for catalytically treatingcontaminated water is characterized by the hereinabove previouslydescribed selected details regarding the chemical bonding between thecomponents of the zero valent metal composite, and is characterized bythe hereinabove previously described selected details regarding thefunctions of the components (powdered diatomite matrix, zero valentmetal particles, electron transfer mediator, and, optionally,vermiculite) of the zero valent metal composite.

Exposing the Contaminated Water to the Zero Valent Metal Composite:

Exposing the contaminated water to the zero valent metal composite ofthe present invention can be performed according to any of a variety ofdifferent ways well known in the art for forming a heterogeneouscatalytic reaction mixture. For example, for implementing the presentinvention, the manner of exposure is such that the contaminated water,for example, in the form of contaminated sub-surface water, surfacewater, or above-surface water, and the zero valent metal composite, areboth stationary in a batch mode, or, alternatively, one or both of whichis/are moving in a flow mode, while the various heterogeneous catalyticreaction processes take place for catalytically treating thecontaminated water.

Batch Mode:

For the exposure being performed in a stationary or batch mode, thecontaminated water is brought into physicochemical contact with thecatalytically effective amount of the zero valent metal composite, or,equivalently, the catalytically effective amount of the zero valentmetal composite is brought into physicochemical contact with thecontaminated water, such that the resulting heterogeneous catalyticreaction mixture is characterized by both the contaminated water and thezero valent metal composite being essentially stationary while thevarious heterogeneous catalytic reaction processes take place, at themolecular and atomic levels, for catalytically treating the contaminatedwater. Such manner of exposure is used for operating the well knownbatch type of heterogeneous catalytic chemical reactor, which is clearlyapplicable for implementing the present invention.

Flow Mode:

For the exposure being performed in a motion or flow mode, thecontaminated water is brought into physicochemical contact with thecatalytically effective amount of the zero valent metal composite whilethe zero valent metal composite remains essentially stationary, suchthat the resulting heterogeneous catalytic reaction mixture ischaracterized by the contaminated water being in dynamic motion orflowing relative to the zero valent metal composite, while the variousheterogeneous catalytic reaction processes take place, at the molecularand atomic levels, for catalytically treating the contaminated water.Alternatively, the catalytically effective amount of the zero valentmetal composite is brought into physicochemical contact with thecontaminated water while the contaminated water remains essentiallystationary, such that the resulting heterogeneous catalytic reactionmixture is characterized by the zero valent metal composite being indynamic motion or flowing relative to the contaminated water, while thevarious heterogeneous catalytic reaction processes take place, at themolecular and atomic levels, for catalytically treating the contaminatedwater. Alternatively, both the contaminated water and the catalyticallyeffective amount of the zero valent metal composite are brought intophysicochemical contact with each other, such that the resultingheterogeneous catalytic reaction mixture is characterized by both thecontaminated water and the zero valent metal composite being in dynamicmotion or flowing relative to each other, while the variousheterogeneous catalytic reaction processes take place for catalyticallytreating the contaminated water. Such manners of exposure are used foroperating the well known flow and fluidized types of heterogeneouscatalytic chemical reactors, which are clearly applicable forimplementing the present invention.

Extent of Time or Duration of Exposing the Contaminated Water to theZero Valent Metal Composite:

In general, for the exposure being performed in a stationary or batchmode, or, alternatively, being performed in a motion or flow mode, theextent of time or duration (for example, hours, days, weeks, etc.) ofexposing the contaminated water to the zero valent metal compositedepends upon the same primary, secondary, and tertiary, parameters of agiven system, as described hereinabove, which determine the actualcatalytically effective amount of the zero valent metal composite neededto practice the invention. In particular, the extent of time or durationof exposing the contaminated water to the zero valent metal compositedepends upon the primary parameters of the types, quantities,concentrations, and, physicochemical and hydrodynamic (flow) properties,characteristics, and behavior, of the contaminated water, of theindividual contaminants in the water, and of the zero valent metalcomposite, throughout the catalytic reaction zone or region; and dependsupon the secondary parameters of temperatures and pressures, andpossible gradients thereof, of the contaminated water, of the individualcontaminants in the water, and of the zero valent metal composite,within the catalytic reaction zone or region; and depends upon thetertiary parameters which correspond to the just indicated primary andsecondary parameters, but with respect to other material(s) possiblypresent throughout, or/and in the immediate vicinity surrounding, thecatalytic reaction zone or region.

For implementing the present invention, preferably, the manner ofexposure is such that the contaminated water, for example, in the formof contaminated sub-surface water, surface water, or above-surfacewater, naturally or forcibly, flows through, and is brought intophysicochemical contact with, the zero valent metal composite while thezero valent metal composite remains essentially stationary. Moreover,preferably, the manner of exposure is such that the volumetric flow rateof the contaminated water, naturally or forcibly, flowing through thezero valent metal composite is at least equal to or larger than thevolumetric flow rate of the contaminated water, naturally or forcibly,flowing through the ground or material immediately surrounding the zerovalent metal composite. Accordingly, preferably, the manner of exposureis such that the permeability, k, of the zero valent metal composite isat least equal to or larger than the permeability, k, of the ground ormaterial immediately surrounding the zero valent metal composite.Preferably, exposing the contaminated water to the zero valent metalcomposite is performed in a manner, for example, under anaerobicconditions, such that only contaminant species in the contaminatedwater, and not non-contaminant species (such as oxygen gas) in thecontaminated water or/and in the immediate vicinity of the contaminatedwater, are catalytically reduced by the zero valent metal particles inthe composite.

As described hereinbelow and illustrated in FIGS. 4-8, such preferredways of exposing the contaminated water to the zero valent metalcomposite are applicable to any of several different embodiments of thesystem of the present invention wherein the zero valent metal compositeis contained in at least one unit located in a flow path as part of anoverall system used for processing or treating the contaminated water.

For implementing the method for catalytically treating contaminatedwater, a system (further described hereinbelow and illustrated in FIGS.4-8) can be used, which preferably includes any of the hereinabovepreviously described embodiments of the zero valent metal composite, andat least one unit, for example, in the form of at least part of asub-surface water permeable reactive barrier (PRB) configured as acontinuous filled in trench, wall, or well, or, in the form of part of asub-surface water or above-surface water pumping and treatment system,for containing the catalytically effective amount of the zero valentmetal composite, for exposing the contaminated water to the zero valentmetal composite.

The hereinabove illustratively described method for catalyticallytreating contaminated water, of the present invention, is generallyapplicable to (in-situ or ex-situ) catalytically treating any of a widevariety of different forms of contaminated water, for example,sub-surface water, surface water, above-surface water, water vapor,gaseous water, or any combination thereof, which are contaminated withany number of a wide variety of different types or kinds of organicor/and inorganic chemical contaminants. The method for catalyticallytreating contaminated water, of the present invention, is particularlyapplicable to (in-situ or ex-situ) catalytically treating such forms ofcontaminated water wherein the water contaminants are organic species,for example, halogenated organic compounds and halogen containingdegradation products thereof; inorganic species, for example, metalelements, metal element containing inorganic species, nonmetal elements,and nonmetal element containing inorganic species; or any combinationthereof. The method for catalytically treating contaminated water, ofthe present invention, is also applicable to (in-situ or ex-situ)catalytically treating contaminated non-aqueous fluids (in liquid,vapor, or/and gaseous forms), for decreasing contaminant concentrationstherefrom.

According to another main aspect of the present invention, the systemfor catalytically treating contaminated water includes the maincomponents of: (a) a zero valent metal composite comprised of a powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having a size in a range of between about 1 nm and about 1000nm and at least one electron transfer mediator, and (b) at least oneunit for containing a catalytically effective amount of the zero valentmetal composite, for exposing the contaminated water to the zero valentmetal composite. Use of the system of the present invention results indecreasing the concentration of at least one contaminant in thecontaminated water.

In the same manner as for the method for catalytically treatingcontaminated water, of the present invention, the system forcatalytically treating contaminated water, of the present invention, isreadily implemented by using any of the hereinabove previously describedembodiments of the zero valent metal composite of the present invention.In particular, a zero valent metal composite composed of a powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having a size in a range of between about 1 nm and about 1000nm and at least one electron transfer mediator, or, alternatively, azero valent metal composite composed of a composition consistingessentially of a powdered diatomite matrix on or/and in which isincorporated zero valent metal particles having a size in a range ofbetween about 1 nm and about 1000 nm and at least one electron transfermediator, or, alternatively, a zero valent metal composite composed of apowdered diatomite matrix on or/and in which is incorporated zero valentmetal particles having a size in a range of between about 1 nm and about1000 nm and at least one electron transfer mediator, and additionallyincludes vermiculite.

Accordingly, the zero valent metal used for implementing the system forcatalytically treating contaminated water has the hereinabove previouslydescribed and numerically valued structural properties and parameters,in particular, particle size, pore size, and weight (mass) percent, ofthe components (powdered diatomite matrix, nanometer sized zero valentmetal particles, at least one electron transfer mediator, and,optionally, vermiculite) of the zero valent metal composite, and has thehereinabove previously described and numerically valued physicochemicalproperty or parameter of permeability, k. Moreover, the zero valentmetal used for catalytically treating contaminated water ischaracterized by the hereinabove previously described selected detailsregarding the chemical bonding between the components of the zero valentmetal composite, and is characterized by the hereinabove previouslydescribed selected details regarding the functions of the components(powdered diatomite matrix, zero valent metal particles, electrontransfer mediator, and, optionally, vermiculite) of the zero valentmetal composite.

For implementing the method and system for catalytically treatingcontaminated water, of the present invention, an in-situ unit isessentially physically (spatially) situated or located, and operative,at or within the actual site, place, or location, of the contaminatedwater, during the catalytic treatment (remediation, purification)process. Accordingly, an in-situ unit is in hydrodynamic communicationwith the contaminated water by means associated with, and correspondingto, the coinciding (generally same) physical (spatial) locations of thein-situ unit and the contaminated water. An ex-situ unit is essentiallyphysically (spatially) situated or located, and operative, out of oraway from the actual site, place, or location, of the contaminatedwater, during the catalytic treatment (remediation, purification)process. Accordingly, an ex-situ unit is in hydrodynamic communicationwith the contaminated water by means associated with, and correspondingto, the non-coinciding (generally separate) physical (spatial) locationsof the ex-situ unit and the contaminated water.

Reference is again made to FIGS. 4-8, wherein are shown exemplaryapplicable in-situ and ex-situ units for containing the catalyticallyeffective amount of the zero valent metal composite. An in-situ unit isin a form as at least part of a sub-surface water permeable reactivebarrier (PRB) configured as a continuous filled in trench or wall (forexample, in-situ unit 20 (FIG. 4)), or as a stand-alone filled in well(for example, in-situ units 30 (FIG. 5)), or in a form as part of asub-surface water pumping and treatment system (for example, in-situunit 32 (FIG. 6)). An exemplary applicable ex-situ unit for containingthe catalytically effective amount of the zero valent metal composite isin a form as part of an above-surface water pumping and treatmentreactor system (for example, ex-situ unit 48 (FIG. 7)). For treatingcontaminated water particularly being as a form of water vapor or/andgaseous water, an exemplary applicable in-situ or ex-situ unit forcontaining the zero valent metal composite is in a form as part of avariably locatable (sub-surface or above-surface) water treatmentreactor system (for example, in-situ or ex-situ unit 70 (FIG. 8).

As used herein, consistent with that used in the art of contaminatedsub-surface water treatment (remediation, purification), a sub-surfacepermeable reactive barrier (PRB) is a closed or open structure orconfiguration, such as a filled in trench, wall, or well, or a system ofseveral closed or/and open structures or configurations, that providespassive interception and in-situ treatment of contaminated sub-surfacewater (e.g., ground water, aquifer water). A sub-surface permeablereactive barrier is characterized by having a permeable zone containingor creating a reactive treatment area, including a highly reactivematerial, for example, zero valent metal (ZVM) particles, andoptionally, also including one or more less reactive, inactive, or/andnon-reactive, materials, oriented to intercept and remediate or purify asub-surface water (e.g., ground water, aquifer water) contaminant plume(i.e., a specific sub-surface region or zone concentrated withcontaminants), by direct exposure of the water contaminants to thereactive material.

Ideally, a sub-surface permeable reactive barrier provides apreferential flow path of the contaminated sub-surface water (e.g.,ground water, aquifer water) through the reactive material, and theother possibly present materials, and degrades, transforms, or/andconverts, the water contaminants into environmentally acceptable(non-hazardous or/and less hazardous) species which exit the barrier,while minimally disrupting natural flow of the sub-surface water (e.g.,ground water, aquifer water). Typically, the contaminated sub-surfacewater (e.g., ground water, aquifer water) flows by natural flow(pressure or current) gradients through the sub-surface PRB, however,pumping schemes configured upstream, within, or/and downstream, thesub-surface PRB, can also be used for implementing a sub-surface PRBsetup. A sub-surface PRB can be installed as a permanent orsemi-permanent closed or open structure or configuration spanning alongor/and across the flow path of a sub-surface water contaminant plume.Alternatively, a sub-surface PRB can be installed as a construction orconfiguration as part of an in-situ reactor which is readily accessibleto facilitate the removal or/and replacement of the spent (deactivated)reactive zero valent metal material, and the other possibly presentmaterials.

Reference is made to FIGS. 4-8, which are schematic diagrams eachillustrating a cut-away view of different exemplary specific preferredembodiments of implementing the method and system for catalyticallytreating contaminated water, of the present invention.

FIG. 4 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, as described hereinabove. The contaminatedwater is in the form of a natural flow of sub-surface water, and thecatalytically effective amount of the zero valent metal composite isdispersed throughout and contained within an in-situ unit being in aform as the lower portion of a sub-surface water permeable reactivebarrier (PRB) configured as a continuous filled in trench or wall.

As shown in FIG. 4, sub-surface water 10, contaminated with any numberand types or kinds of organic or/and inorganic chemical contaminants 12(indicated in 10 by the filled in irregularly shaped forms), naturallyflows (indicated in 10 by the arrows pointing toward the rightdirection) between sub-surface regions 14, located beneath top surfaceregion 16. A catalytically effective amount of zero valent metalcomposite 18 is dispersed throughout and contained within an in-situunit 20 being in a form as the lower portion of a sub-surface waterpermeable reactive barrier (PRB) 22 configured as a continuous filled intrench or wall, whose upper portion 24 is filled with an inactive or/anda non-reactive filler material 26.

In-situ unit 20 is structured and functions for containing thecatalytically effective amount of zero valent metal composite 18, andfor enabling the exposing of the natural flow of contaminatedsub-surface water (10 plus 12) to the catalytically effective amount ofzero valent metal composite 18. Moreover, in-situ unit 20 is structuredand functions according to heterogeneous catalysis, via a flow mode. Thevarious heterogeneous catalytic reaction processes take place (underreducing (anaerobic or anoxic) conditions) within the flowingcontaminated sub-surface water (10 plus 12), for heterogeneouslycatalytically treating the flowing contaminated sub-surface water (10plus 12), to thereby decrease the concentration of at least one ofchemical contaminants 12 in contaminated sub-surface water (10 plus 12).Accordingly, flowing sub-surface water 10 exiting (to the right of)in-situ unit 20 has been catalytically treated (remediated or purified)with respect to a decrease in concentration of at least one of chemicalcontaminants 12.

FIG. 5 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, as described hereinabove. The contaminatedwater is in the form of a natural flow of sub-surface water, and thecatalytically effective amount of the zero valent metal composite isdispersed throughout and contained within each of a plurality of in-situunits each being in a form as a sub-surface water permeable reactivebarrier (PRB) configured as a stand-alone filled in well.

As shown in FIG. 5, sub-surface water 10, contaminated with any numberand types or kinds of organic or/and inorganic chemical contaminants 12(indicated in 10 by the filled in irregularly shaped forms), naturallyflows (indicated in 10 by the arrows pointing toward the rightdirection) between sub-surface regions 14, located beneath top surfaceregion 16. A catalytically effective amount of zero valent metalcomposite 18 is dispersed throughout and contained within each of aplurality of (for example, six) in-situ units 30 each being in a form asa sub-surface water permeable reactive barrier (PRB) configured as astand-alone filled in well.

Each of the in-situ units 30 is structured and functions for containingthe catalytically effective amount of zero valent metal composite 18,and for enabling the exposing of the natural flow of contaminatedsub-surface water (10 plus 12) to the catalytically effective amount ofzero valent metal composite 18. Moreover, each of the in-situ units 30is structured and functions according to heterogeneous catalysis, via aflow mode. The various heterogeneous catalytic reaction processes takeplace (under reducing (anaerobic or anoxic) conditions) within theflowing contaminated sub-surface water (10 plus 12), for heterogeneouslycatalytically treating the flowing contaminated sub-surface water (10plus 12), to thereby decrease the concentration of at least one ofchemical contaminants 12 in contaminated sub-surface water (10 plus 12).Accordingly, flowing sub-surface water 10 exiting (to the right of)in-situ units 30 has been catalytically treated (remediated or purified)with respect to a decrease in concentration of at least one of chemicalcontaminants 12.

FIG. 6 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, as described hereinabove. The contaminatedwater is in the form of a natural and forced flow of sub-surface water,and the catalytically effective amount of the zero valent metalcomposite is dispersed throughout and contained within an in-situ unitbeing in a form as part of a sub-surface water pumping and treatmentsystem.

As shown in FIG. 6, sub-surface water 10, contaminated with any numberand types or kinds of organic or/and inorganic chemical contaminants 12(indicated in 10 by the filled in irregularly shaped forms), in additionto any possible natural flow (indicated in 10 by the single arrowpointing towards the right direction), forcibly flows, via pumping by asub-surface water pumping device 36, (indicated in 10 by the two sets ofarrows each pointing towards water pumping device 36) betweensub-surface regions 14, located beneath top surface region 16. Acatalytically effective amount of zero valent metal composite 18 isdispersed throughout and contained within an in-situ unit 32 being in aform as the middle part of a sub-surface water pumping and treatmentsystem (36, 32, and 40).

Contaminated sub-surface water (10 plus 12) is pumped and forciblyflows, into and through the volume and contents 34 of sub-surface waterpumping device 36, via pumping by water pumping device 36 located at thelower portion of sub-surface water pumping and treatment system (36, 32,and 40). Contaminated sub-surface water (10 plus 12) is then pumped andforcibly flows upward, into, and through, the catalytically effectiveamount of zero valent metal composite 18 contained within in-situ unit32 located in the middle portion of sub-surface water pumping andtreatment system (36, 32, and 40). Catalytically treated (remediated orpurified) sub-surface water 10 is then pumped and forcibly flows upward,into, and through, the volume and contents 38 of a treated watercollection/passage chamber 40 located in the upper portion ofsub-surface water pumping and treatment system (36, 32, and 40). Thecatalytically treated sub-surface water 10 then exits through the topportion of treated water collection/passage chamber 40, as indicated by42.

In-situ unit 32 is structured and functions for containing thecatalytically effective amount of zero valent metal composite 18, andfor enabling the exposing of the natural and forced flow of contaminatedsub-surface water (10 plus 12) to the catalytically effective amount ofzero valent metal composite 18, under reducing (anaerobic or anoxic)conditions. Moreover, in-situ unit 32 is structured and functionsaccording to heterogeneous catalysis, via a flow mode. The variousheterogeneous catalytic reaction processes take place (under reducing(anaerobic or anoxic) conditions) within the flowing contaminatedsub-surface water (10 plus 12), for heterogeneously catalyticallytreating the flowing contaminated sub-surface water (10 plus 12), tothereby decrease the concentration of at least one of chemicalcontaminants 12 in contaminated sub-surface water (10 plus 12).Accordingly, flowing sub-surface water 42 exiting through the topportion of treated water collection/passage chamber 40 has beencatalytically treated (remediated or purified) with respect to adecrease in concentration of at least one of chemical contaminants 12.

FIG. 7 is a schematic diagram illustrating a cut-away view of threeexemplary specific configurations, of exemplary specific preferredembodiments of implementing the method and system for catalyticallytreating contaminated water, according to heterogeneous catalysis, via abatch or flow mode, as described hereinabove. The contaminated water isin the form(s) of (natural or/and forced) flow of sub-surface water,surface water, or/and above-surface water, and the catalyticallyeffective amount of the zero valent metal composite is dispersedthroughout and contained within an ex-situ unit being in a form as partof an above-surface water treatment reactor system.

First Configuration:

According to the first configuration shown in FIG. 7, sub-surface water10, contaminated with any number and types or kinds of organic or/andinorganic chemical contaminants 12 (indicated in 10 by the filled inirregularly shaped forms), in addition to any possible natural flow(indicated in 10 by the single arrow pointing towards the rightdirection), forcibly flows, via pumping by a sub-surface water pumpingdevice 46, (indicated in 10 by the two sets of arrows each pointingtowards sub-surface water pumping device 46) between sub-surface regions14, located beneath top surface region 16.

In the first configuration, a catalytically effective amount of zerovalent metal composite 18 is contained within an ex-situ unit 48 beingin a form as part of an above-surface water treatment reactor system 50.Contaminated sub-surface water (10 plus 12) is pumped and forciblyflows, into and through the volume and contents 44 of sub-surface waterpumping device 46, from sub-surface water pumping device 46, via a watertransport line (pipe) 52, into ex-situ unit 48 of above-surface watertreatment reactor system 50, and is then exposed to the catalyticallyeffective amount of zero valent metal composite 18. Catalyticallytreated (remediated or purified) sub-surface water 10 then exits out ofabove-surface water treatment reactor system 50, as indicated by 54.

Ex-situ unit 48 is structured and functions for containing thecatalytically effective amount of zero valent metal composite 18, andfor enabling the exposing of the natural and forced flow of contaminatedsub-surface water (10 plus 12) to the catalytically effective amount ofzero valent metal composite 18, under reducing (anaerobic or anoxic)conditions. Moreover, ex-situ unit 48 is structured and functionsaccording to heterogeneous catalysis, via a batch or flow mode. Thevarious heterogeneous catalytic reaction processes take place (underreducing (anaerobic or anoxic) conditions) within a batch or flow of thecontaminated sub-surface water (10 plus 12), for heterogeneouslycatalytically treating the flowing contaminated sub-surface water (10plus 12), to thereby decrease the concentration of at least one ofchemical contaminants 12 in contaminated sub-surface water (10 plus 12).Accordingly, sub-surface water 54 exiting out of above-surface watertreatment reactor system 50 has been catalytically treated (remediatedor purified) with respect to a decrease in concentration of at least oneof chemical contaminants 12.

Second Configuration:

According to the second configuration shown in FIG. 7, surface water 56,for example, of a river, stream, lake, pond, pool, surface waterreservoir, or, well or spring, whose top or uppermost surface is locatedat about ground or earth level, herein, generally indicated as 58,contaminated with any number and types or kinds of organic or/andinorganic chemical contaminants 12 (indicated in 56 by the filled inirregularly shaped forms), is located along top surface region 16.

In the second configuration, the catalytically effective amount of zerovalent metal composite 18 is dispersed throughout and contained withinan ex-situ unit 48 being in a form as part of an above-surface watertreatment reactor system 50. Contaminated surface water (56 plus 12), inaddition to any possible natural flow (indicated in 56 by the two arrowspointing toward the right direction), is pumped and forcibly flows, fromriver, stream, lake, pond, pool, surface water reservoir, or, well orspring, 58, via a water transport line (pipe) 60, into ex-situ unit 48of above-surface water treatment reactor system 50, and is then exposedto the catalytically effective amount of zero valent metal composite 18.Catalytically treated (remediated or purified) surface water 56 thenexits out of above-surface water treatment reactor system 50, asindicated by 54.

Ex-situ unit 48 is structured and functions for containing thecatalytically effective amount of zero valent metal composite 18, andfor enabling the exposing of the natural and forced flow of contaminatedsurface water (56 plus 12) to the catalytically effective amount of zerovalent metal composite 18, under reducing (anaerobic or anoxic)conditions. Moreover, ex-situ unit 48 is structured and functionsaccording to heterogeneous catalysis, via a batch or flow mode. Thevarious heterogeneous catalytic reaction processes take place (underreducing (anaerobic or anoxic) conditions) within a batch or flow of thecontaminated surface water (56 plus 12), for heterogeneouslycatalytically treating the flowing contaminated surface water (56 plus12), to thereby decrease the concentration of at least one of chemicalcontaminants 12 in contaminated surface water (56 plus 12). Accordingly,surface water 56 exiting out of above-surface water treatment reactorsystem 50 has been catalytically treated (remediated or purified) withrespect to a decrease in concentration of at least one of chemicalcontaminants 12.

Third Configuration:

According to the third configuration shown in FIG. 7, above-surfacewater 62, for example, of an above-surface water reservoir, or of anabove-surface source or supply of residential or commercial drinkingwater, herein, generally indicated as 64, contaminated with contaminatedwith any number and types or kinds of organic or/and inorganic chemicalcontaminants 12 (present, but not indicated, in 62, in FIG. 7) islocated on and above top surface region 16.

In the third configuration, the catalytically effective amount of zerovalent metal composite 18 is dispersed throughout and contained withinan ex-situ unit 48 being in a form as part of an above-surface watertreatment reactor system 50. Contaminated above-surface water (62 plus12) is pumped and forcibly flows, from above-surface water reservoir, orabove-surface source or supply of residential or commercial drinkingwater, 64, via a water transport line (pipe) 66, into ex-situ unit 48 ofabove-surface water treatment reactor system 50, and is then exposed tothe catalytically effective amount of zero valent metal composite 18.Catalytically treated (remediated or purified) above-surface water 62then exits out of above-surface water treatment reactor system 50, asindicated by 54.

Ex-situ unit 48 is structured and functions for containing thecatalytically effective amount of zero valent metal composite 18, andfor enabling the exposing of the natural and forced flow of contaminatedabove-surface water (62 plus 12) to the catalytically effective amountof zero valent metal composite 18, under reducing (anaerobic or anoxic)conditions. Moreover, ex-situ unit 48 is structured and functionsaccording to heterogeneous catalysis, via a batch or flow mode. Thevarious heterogeneous catalytic reaction processes take place (underreducing (anaerobic or anoxic) conditions) within a batch or flow of thecontaminated above-surface water (62 plus 12), for heterogeneouslycatalytically treating the flowing contaminated above-surface water (62plus 12), to thereby decrease the concentration of at least one ofchemical contaminants 12 in contaminated above-surface water (62 plus12). Accordingly, above-surface water 62 exiting out of above-surfacewater treatment reactor system 50 has been catalytically treated(remediated or purified) with respect to a decrease in concentration ofat least one of chemical contaminants 12.

FIG. 8 is a schematic diagram illustrating a cut-away view of exemplaryspecific preferred embodiments of implementing the method and system forcatalytically treating contaminated water, according to heterogeneouscatalysis, via a flow mode, as described hereinabove. The contaminatedwater is in the form of water vapor or/and gaseous water, and thecatalytically effective amount of the zero valent metal composite isdispersed throughout and contained within an in-situ or ex-situ unitbeing in a form as part of a variably locatable (sub-surface orabove-surface) water treatment reactor system.

As shown in FIG. 8, contaminated water 72, in the form(s) of water vaporor/and gaseous water (which may also include non-water (i.e.,non-aqueous) vapor or/and gaseous species as part of a multi-component,multi-phase, vapor or/and gas mixture), contaminated with any number andtypes or kinds of organic or/and inorganic chemical contaminants,naturally or/and forcibly flows (as indicated by the filled in arrowpointing towards the right direction), into a variably locatable(sub-surface or above-surface) water treatment reactor system (74, 70,and 78). A catalytically effective amount of zero valent metal composite18 is dispersed throughout and contained within an in-situ or ex-situunit 70 being in a form as part of variably locatable (sub-surface orabove-surface) water treatment reactor system (74, 70, and 78).

Contaminated water vapor or/and gaseous water 72 naturally or/andforcibly flows into and through contaminated water vapor or/and gaseouswater input chamber or module 74, and then into and through zero valentmetal composite 18 dispersed throughout and contained within in-situ orex-situ unit 70. Catalytically treated (remediated or purified) watervapor or/and gaseous water 76 then naturally or/and forcibly flows (asindicated by the non-filled in arrow pointing towards the rightdirection) into, through, and exits out of, treated water vapor or/andgaseous water output chamber or module 78, of (sub-surface orabove-surface) water treatment reactor system (74, 70, and 78).

In-situ or ex-situ unit 70 is structured and functions for containingthe catalytically effective amount of zero valent metal composite 18,and for enabling the exposing of the natural or/and forced flow ofcontaminated water vapor or/and gaseous water 72 to the catalyticallyeffective amount of zero valent metal composite 18, under reducing(anaerobic or anoxic) conditions. Moreover, in-situ or ex-situ unit 70is structured and functions according to heterogeneous catalysis, via aflow mode. The various heterogeneous catalytic reaction processes takeplace (under reducing (anaerobic or anoxic) conditions) within theflowing contaminated water vapor or/and gaseous water 72, forheterogeneously catalytically treating the flowing contaminated watervapor or/and gaseous water 72, to thereby decrease the concentration ofat least one of the chemical contaminants in contaminated water vaporor/and gaseous water 72. Accordingly, flowing water vapor or/and gaseouswater 76 exiting (to the right of) in-situ or ex-situ unit 70 has beencatalytically treated (remediated or purified) with respect to adecrease in concentration of at least one of the chemical contaminants.

It is important to emphasis that for any of the above describedexemplary specific preferred embodiments of implementing the method andsystem for catalytically treating contaminated water, of the presentinvention, as illustrated in FIGS. 4-8, according to heterogeneouscatalysis, via a flow or batch mode, the in-situ or ex-situ unit isstructured and functions according to heterogeneous catalysis, via aflow or batch mode. The inclusion of the zero valent metal particles(functioning as a bulk electron donor or reducing agent) in the zerovalent metal composite provides for, and enables, the variousheterogeneous catalytic reaction processes to take place under reducing(anaerobic or anoxic) conditions within a flow or batch of thecontaminated water, for heterogeneously catalytically treating the flowor batch of contaminated above-surface water, to thereby decrease theconcentration of at least one of the chemical contaminants in thecontaminated water. Accordingly, exposure of the contaminated water tothe catalytically effective amount of the zero valent metal compositetakes place under reducing (anaerobic or anoxic) conditions, i.e., asopposed to oxidizing conditions.

As for the hereinabove illustratively described corresponding method,the hereinabove illustratively described system for catalyticallytreating contaminated water, of the present invention, is generallyapplicable to (in-situ or ex-situ) catalytically treating any of a widevariety of different forms of contaminated water, for example,sub-surface water, surface water, above-surface water, water vapor,gaseous water, or any combination thereof, which are contaminated withany number of a wide variety of different types or kinds of organicor/and inorganic chemical contaminants. The system for catalyticallytreating contaminated water, of the present invention, is particularlyapplicable to (in-situ or ex-situ) catalytically treating such forms ofcontaminated water wherein the water contaminants are organic species,for example, halogenated organic compounds and halogen containingdegradation products thereof; inorganic species, for example, metalelements, metal element containing inorganic species, nonmetal elements,and nonmetal element containing inorganic species; or any combinationthereof. The system for catalytically treating contaminated water, ofthe present invention, is also applicable to (in-situ or ex-situ)catalytically treating contaminated non-aqueous fluids (in liquid,vapor, or/and gaseous forms), for decreasing contaminant concentrationstherefrom.

In general, for any of the above described exemplary specific preferredembodiments of implementing the method and system for catalyticallytreating contaminated water, of the present invention, of the presentinvention, as illustrated in FIGS. 4-8, according to heterogeneouscatalysis, via a flow or batch mode, following heterogeneous catalytictreatment of the contaminated water, the zero valent metal composite 18can be removed from the associated in-situ unit(s) [e.g., in-situ unit20 (FIG. 4), in-situ units 30 (FIG. 5), in-situ unit 32 (FIG. 6),in-situ unit 70 (FIG. 8)], or ex-situ unit(s) [e.g., ex-situ unit 48(FIG. 7), ex-situ unit 70 (FIG. 8)] used for treating the contaminatedwater, and be recycled for again treating contaminated water. Suchrecycling can include, for example, subjecting the zero valent metalcomposite 18 to a cleaning procedure, involving selective removal of theadsorbed contaminants from the solid support or matrix, whilenon-destructively handling and processing the solid support or matrix.

According to another aspect of the present invention, there is providedan article-of-manufacture including a packaging material, and thehereinabove illustratively described zero valent metal compositecomposed of a powdered diatomite matrix on or/and in which isincorporated zero valent metal particles having a size in a range ofbetween about 1 nm and about 1000 nm and at least one electron transfermediator, being contained within the packaging material, the compositebeing identified for use in catalytically treating contaminated water.

According to another aspect of the present invention, there is provideda an article-of-manufacture including a packaging material, and thehereinabove illustratively described zero valent metal compositecomposed of a composition consisting essentially of a powdered diatomitematrix on or/and in which is incorporated zero valent metal particleshaving a size in a range of between about 1 nm and about 1000 nm and atleast one electron transfer mediator, being contained within thepackaging material, the composite being identified for use incatalytically treating contaminated water.

In general, any of the above illustratively described embodiments orformulations of the zero valent metal composite, of the presentinvention, is suitable as being contained within the packaging materialof the article-of-manufacture, wherein the composite is identified foruse in catalytically treating contaminated water. During such use, acatalytically effective amount of the zero valent metal composite isexposed to the contaminated water, to thereby decrease concentration ofat least one contaminant in the contaminated water.

For each embodiment of the article-of-manufacture, preferably, thepackaging material is made and constructed of materials which are inertto, and minimally, if at all, ‘chemically’ interact with, any of thecomponents of the zero valent metal composite.

Above illustratively described novel and inventive aspects andcharacteristics, and advantages thereof, of the present inventionfurther become apparent to one ordinarily skilled in the art uponexamination of the following examples, which are not intended to belimiting. Additionally, each of the various embodiments and aspects ofthe present invention as delineated herein above and as claimed in theclaims section below finds experimental support in the followingexamples.

EXAMPLES

Reference is now made to the following examples, Examples 1-9, whichtogether with the above descriptions, illustrate the invention in anon-limiting fashion.

Example 1 Manufacturing (Synthesis) of a Zero Valent Metal Composite(without Vermiculite)

A zero valent metal composite was manufactured (synthesized) accordingto the hereinabove described exemplary preferred embodiment of themanufacturing method (without optional addition of vermiculite). Thezero valent metal composite was a zero valent iron (ZVI) compositecomposed of a powdered diatomite matrix on or/and in which isincorporated zero valent iron particles having a size in a range ofbetween about 1 nm and about 1000 nm and vitamin B₁₂.

Preparation of an Aqueous Solution of a Metal Salt:

An iron metal alkali salt, ferric (iron (III)) chloride hexahydrate(FeCl₃.6H₂O) (0.1 mole), was dissolved in water (100 ml). The aqueoussolution of the ferric chloride was placed in a 500 ml filter flask inan anaerobic chamber.

Preparation of an Aqueous Solution of the Electron Transfer Mediator:

The electron transfer mediator used in the synthesis was theporphyrinogenic organometallic complex, being the metallocorrin complex,vitamin B₁₂. A 2 mM aqueous solution of vitamin B₁₂ was prepared.

Addition of the Aqueous Solution of the Electron Transfer Mediator tothe Aqueous Solution of the Metal Salt, for Forming an Aqueous Solutionof the Metal Salt and the Electron Transfer Mediator:

A volume (9.31 ml) of the 2 mM aqueous solution of vitamin B₁₂ was addedto the aqueous solution of the ferric chloride, for forming an aqueoussolution of the ferric chloride and the vitamin B₁₂.

Addition of a Powdered Form of Diatomite (Kieselguhr) to the AqueousSolution of the Metal Salt and the Electron Transfer Mediator, forForming an Aqueous Slurry of the Metal Salt, the Electron TransferMediator, and the Powdered Diatomite Matrix:

A powdered form of diatomite (kieselguhr) (about 1 mole) was added tothe aqueous solution of the ferric chloride and the vitamin B₁₂, forforming an aqueous slurry of the ferric chloride, the vitamin B₁₂, andthe powdered diatomite matrix. Additional water (100 ml) was added tothe aqueous slurry which was initially formed upon commencing additionof the powdered form of the diatomite. The aqueous slurry of the ferricchloride, the vitamin B₁₂, and the powdered diatomite matrix, was of aconsistency which could be mixed by magnetic stirring. The aqueousslurry was then placed in a fume hood and mixed by a magnetic stirrer.

Preparation of an Aqueous Solution of a Strong Reducing Agent:

An aqueous solution of a strong reducing agent was prepared bydissolving sodium borohydride (NaBH₄) (0.3 mole) in water (100 ml), inan amber bottle, which was placed in an anaerobic chamber.

Forming and Initiating Reaction of a Redox Reaction Mixture of theAqueous Slurry of the Metal Salt, the Electron Transfer Mediator, andthe Powdered Diatomite Matrix, with the Aqueous Solution of the StrongReducing Agent:

The aqueous slurry of the ferric chloride, the vitamin B₁₂, and thepowdered diatomite matrix, and, the aqueous solution of the sodiumborohydride, were each placed on a magnetic stirrer in a fume hood.Forming and initiating reaction of the redox reaction mixture wasperformed by pumping and drop-wise adding the aqueous solution of thesodium borohydride to the reaction vessel containing the aqueous slurry,while mixing, and supplying nitrogen inert gas to the reaction vesselfor preventing intrusion of oxygen.

Allowing the Redox Reaction Mixture to React to Completion, for Forminga Product Mixture of the Zero Valent Metal Composite in Water:

The redox reactive mixture was allowed to react to completion, upondelivering all of the sodium borohydride to the reaction vesselcontaining the aqueous slurry, for forming a product mixture of the zerovalent iron composite in water.

Collecting the Zero Valent Metal Composite:

The zero valent iron (ZVI) composite was transferred to an anaerobicchamber, filtered, and then washed with water (1000 ml) and acetone (200ml).

Drying the Collected Zero Valent Metal Composite, for Forming Dry ZeroValent Metal Composite:

The collected zero valent iron (ZVI) composite was dried in theanaerobic chamber, by using vacuum pumping. Following the dryingprocedure, the dry zero valent iron composite was stored in a closedcontainer in the anaerobic chamber until needed for use.

Components of the zero valent iron composite had the followingnumerically valued structural properties and parameters, with respect toa ‘dry basis’. Particles of the powdered diatomite matrix included inthe zero valent iron composite had a particle size in a range of betweenabout 1 micron and about 150 microns, and had a pore size in a range ofbetween about 1 nm and about 5000 nm. Zero valent iron particlesincorporated on or/and in the powdered diatomite matrix of the zerovalent iron composite had a concentration, in terms of weight (mass)percent, of about 7.7%. The vitamin B₁₂ electron transfer mediatorincorporated on or/and in the powdered diatomite matrix of the zerovalent iron composite had a concentration, in terms of weight percent,of about 0.038%.

Example 2 Manufacturing (Synthesis) of a Zero Valent Metal Composite(Including Vermiculite)

A zero valent metal composite was manufactured (synthesized) accordingto the hereinabove described first exemplary alternative preferredembodiment of the manufacturing method (with optional addition ofvermiculite), i.e., including the optional procedure of addingvermiculite to the aqueous solution of the metal salt, for forming amixture of the vermiculite and the aqueous solution of the metal salt.The zero valent metal composite was a zero valent iron (ZVI) compositecomposed of a powdered diatomite matrix on or/and in which isincorporated zero valent iron particles having a size in a range ofbetween about 1 nm and about 1000 nm and vitamin B₁₂, and includedvermiculite.

Preparation of an Aqueous Solution of a Metal Salt:

An iron metal alkali salt, ferric (iron (III)) chloride hexahydrate(FeCl₃.6H₂O) (0.1 mole), was dissolved in water (100 ml). The aqueoussolution of the ferric chloride was placed in a 500 ml filter flask inan anaerobic chamber.

Addition of Vermiculite to the Aqueous Solution of the Metal Salt, forForming a Mixture of the Vermiculite and the Aqueous Solution of theMetal Salt:

Vermiculite (0.02 mole) was added to the aqueous solution of the ferricchloride, for forming a mixture of the vermiculite and the aqueoussolution of the ferric chloride.

Preparation of an Aqueous Solution of the Electron Transfer Mediator:

The electron transfer mediator used in the synthesis was theporphyrinogenic organometallic complex, being the metallocorrin complex,vitamin B₁₂. A 2 mM aqueous solution of vitamin B₁₂ was prepared.

Addition of the Aqueous Solution of the Electron Transfer Mediator tothe Mixture of the Vermiculite and the Aqueous Solution of the MetalSalt, for Forming a Mixture of the Vermiculite and an Aqueous Solutionof the Metal Salt and the Electron Transfer Mediator:

A volume (9.31 ml) of the 2 mM aqueous solution of vitamin B₁₂ was addedto the mixture of the vermiculite and the aqueous solution of the ferricchloride, for forming a mixture of the vermiculite and an aqueoussolution of the ferric chloride and the vitamin B₁₂.

Addition of a Powdered Form of Diatomite (Kieselguhr) to the Mixture ofthe Vermiculite and the Aqueous Solution of the Metal Salt and theElectron Transfer Mediator, for Forming a Mixture of the Vermiculite andan Aqueous Slurry of the Metal Salt, the Electron Transfer Mediator, andthe Powdered Diatomite Matrix:

A powdered form of diatomite (kieselguhr) (about 1 mole) was added tothe mixture of the vermiculite and the aqueous solution of the ferricchloride and the vitamin B₁₂, for forming a mixture of the vermiculiteand an aqueous slurry of the ferric chloride, the vitamin B₁₂, and thepowdered diatomite matrix. Additional water (100 ml) was added to theaqueous slurry which was initially formed upon commencing addition ofthe powdered form of the diatomite. The mixture of the vermiculite andthe aqueous slurry of the ferric chloride, the vitamin B₁₂, and thepowdered diatomite matrix, was of a consistency which could be mixed bymagnetic stirring. The mixture of the vermiculite and the aqueous slurrywas then placed in a fume hood and mixed by a magnetic stirrer.

Preparation of an Aqueous Solution of a Strong Reducing Agent:

An aqueous solution of a strong reducing agent was prepared bydissolving sodium borohydride (NaBH₄) (0.3 mole) in water (100 ml), inan amber bottle, which was placed in an anaerobic chamber.

Forming and Initiating Reaction of a Redox Reaction Mixture of theVermiculite and the aqueous slurry of the metal salt, the electrontransfer mediator, and the Powdered Diatomite Matrix, with the AqueousSolution of the Strong Reducing Agent:

The mixture of the vermiculite and the aqueous slurry of the ferricchloride, the vitamin B₁₂, and the powdered diatomite matrix, and, theaqueous solution of the sodium borohydride, were each placed on amagnetic stirrer in a fume hood. Forming and initiating reaction of theredox reaction mixture was performed by pumping and drop-wise adding theaqueous solution of the sodium borohydride to the reaction vesselcontaining the aqueous slurry, while mixing, and supplying nitrogeninert gas to the reaction vessel for preventing intrusion of oxygen.

Allowing the Redox Reaction Mixture to React to Completion, for Forminga Product Mixture of the Zero Valent Metal Composite (IncludingVermiculite) in Water:

The redox reactive mixture was allowed to react to completion, upondelivering all of the sodium borohydride to the reaction vesselcontaining the aqueous slurry, for forming a product mixture of the zerovalent iron composite (including vermiculite) in water.

Collecting the Zero Valent Metal Composite (Including Vermiculite):

The zero valent iron (ZVI) composite (including vermiculite) wastransferred to an anaerobic chamber, filtered, and then washed withwater (1000 ml) and acetone (200 ml).

Drying the Collected Zero Valent Metal Composite (IncludingVermiculite), for Forming Dry Zero Valent Metal Composite (IncludingVermiculite):

The collected zero valent iron (ZVI) composite (including vermiculite)was dried in the anaerobic chamber, by using vacuum pumping. Followingthe drying procedure, the dry zero valent iron composite (includingvermiculite) was stored in a closed container in the anaerobic chamberuntil needed for use.

Components of the zero valent iron composite had the followingnumerically valued structural properties and parameters, with respect toa ‘dry basis’. Particles of the powdered diatomite matrix included inthe zero valent iron composite had a particle size in a range of betweenabout 1 micron and about 150 microns, and had a pore size in a range ofbetween about 1 nm and about 5000 nm. Zero valent iron particlesincorporated on or/and in the powdered diatomite matrix of the zerovalent iron composite had a concentration, in terms of weight (mass)percent, of about 7.7%. The vitamin B₁₂ electron transfer mediatorincorporated on or/and in the powdered diatomite matrix of the zerovalent iron composite had a concentration, in terms of weight percent,of about 0.038%.

Vermiculite additionally included in the zero valent iron composite hada piece size in a range of between about 0.01 mm and about 20.0 mm, andhad a concentration, in terms of weight percent, of about 50%.

Example 3 Manufacturing (Synthesis) of a Zero Valent Metal Composite(Including Vermiculite)

A zero valent metal composite was manufactured (synthesized) accordingto the hereinabove described second exemplary alternative preferredembodiment of the manufacturing method (with optional addition ofvermiculite), i.e., including the alternative optional procedure ofadding vermiculite to the collected zero valent metal composite (absentof vermiculite), for forming the zero valent metal composite (includingvermiculite). The zero valent metal composite was a zero valent iron(ZVI) composite composed of a powdered diatomite matrix on or/and inwhich is incorporated zero valent iron particles having a size in arange of between about 1 nm and about 1000 nm and vitamin B₁₂, andincluded vermiculite.

Preparation of an Aqueous Solution of a Metal Salt:

An iron metal alkali salt, ferric (iron (III)) chloride hexahydrate(FeCl₃.6H₂O) (0.1 mole), was dissolved in water (100 ml). The aqueoussolution of the ferric chloride was placed in a 500 ml filter flask inan anaerobic chamber.

Preparation of an Aqueous Solution of the Electron Transfer Mediator:

The electron transfer mediator used in the synthesis was theporphyrinogenic organometallic complex, being the metallocorrin complex,vitamin B₁₂. A 2 mM aqueous solution of vitamin B₁₂ was prepared.

Addition of the Aqueous Solution of the Electron Transfer Mediator tothe Aqueous Solution of the Metal Salt, for Forming an Aqueous Solutionof the Metal Salt and the Electron Transfer Mediator:

A volume (9.31 ml) of the 2 mM aqueous solution of vitamin B₁₂ was addedto the aqueous solution of the ferric chloride, for forming an aqueoussolution of the ferric chloride and the vitamin B₁₂.

Addition of a Powdered Form of Diatomite (Kieselguhr) to the AqueousSolution of the Metal Salt and the Electron Transfer Mediator, forForming an Aqueous Slurry of the Metal Salt, the Electron TransferMediator, and the Powdered Diatomite Matrix:

A powdered form of diatomite (kieselguhr) (about 1 mole) was added tothe aqueous solution of the ferric chloride and the vitamin B₁₂, forforming an aqueous slurry of the ferric chloride, the vitamin B₁₂, andthe powdered diatomite matrix. Additional water (100 ml) was added tothe aqueous slurry which was initially formed upon commencing additionof the powdered form of the diatomite. The aqueous slurry of the ferricchloride, the vitamin B₁₂, and the powdered diatomite matrix, was of aconsistency which could be mixed by magnetic stirring. The aqueousslurry was then placed in a fume hood and mixed by a magnetic stirrer.

Preparation of an Aqueous Solution of a Strong Reducing Agent:

An aqueous solution of a strong reducing agent was prepared bydissolving sodium borohydride (NaBH₄) (0.3 mole) in water (100 ml), inan amber bottle, which was placed in an anaerobic chamber.

Forming and Initiating Reaction of a Redox Reaction Mixture of theAqueous Slurry of the Metal Salt, the Electron Transfer Mediator, andthe Powdered Diatomite Matrix, with the Aqueous Solution of the StrongReducing Agent:

The aqueous slurry of the ferric chloride, the vitamin B₁₂, and thepowdered diatomite matrix, and, the aqueous solution of the sodiumborohydride, were each placed on a magnetic stirrer in a fume hood.Forming and initiating reaction of the redox reaction mixture wasperformed by pumping and drop-wise adding the aqueous solution of thesodium borohydride to the reaction vessel containing the aqueous slurry,while mixing, and supplying nitrogen inert gas to the reaction vesselfor preventing intrusion of oxygen.

Allowing the Redox Reaction Mixture to React to Completion, for Forminga Product Mixture of the Zero Valent Metal Composite in Water:

The redox reactive mixture was allowed to react to completion, upondelivering all of the sodium borohydride to the reaction vesselcontaining the aqueous slurry, for forming a product mixture of the zerovalent iron composite in water.

Collecting the Zero Valent Metal Composite:

The zero valent iron (ZVI) composite was transferred to an anaerobicchamber, filtered, and then washed with water (1000 ml) and acetone (200ml).

Adding Vermiculite to the Collected Zero Valent Metal Composite (Absentof Vermiculite), for Forming the Zero Valent Metal Composite (IncludingVermiculite):

While still in the anaerobic chamber, vermiculite (0.02 mole) was addedto the vermiculite-free collected zero valent iron composite, forforming the zero valent iron composite (including vermiculite). The zerovalent iron composite (including vermiculite) was washed with water(1000 ml) and acetone (200 ml).

Drying the Collected Zero Valent Metal Composite (IncludingVermiculite), for Forming Dry Zero Valent Metal Composite (IncludingVermiculite):

The collected zero valent iron (ZVI) composite (including vermiculite)was dried in the anaerobic chamber, by using vacuum pumping. Followingthe drying procedure, the dry zero valent iron composite (includingvermiculite) was stored in a closed container in the anaerobic chamberuntil needed for use.

Components of the zero valent iron composite had the followingnumerically valued structural properties and parameters, with respect toa ‘dry basis’. Particles of the powdered diatomite matrix included inthe zero valent iron composite had a particle size in a range of betweenabout 1 micron and about 150 microns, and had a pore size in a range ofbetween about 1 nm and about 5000 nm. Zero valent iron particlesincorporated on or/and in the powdered diatomite matrix of the zerovalent iron composite had a concentration, in terms of weight (mass)percent, of about 7.7%. The vitamin B₁₂ electron transfer mediatorincorporated on or/and in the powdered diatomite matrix of the zerovalent iron composite had a concentration, in terms of weight percent,of about 0.038%.

Vermiculite additionally included in the zero valent iron composite hada piece size in a range of between about 0.01 mm and about 20.0 mm, andhad a concentration, in terms of weight percent, of about 50%.

Example 4 Physical and Chemical Analysis and Characterization of a ZeroValent Metal Composite

Selected samples of the ‘clean’ (pre-treated, pre-reacted) powdereddiatomite used for manufacturing (synthesizing) the different specificembodiments of the zero valent iron composite, as described hereinaboveand exemplified in Examples 1, 2, and 3, and of the zero valent ironcomposite manufactured (synthesized) as described and exemplifiedhereinabove in Example 1, in accordance with the present invention, weresubjected to visual (naked eye) and, physical and chemical instrumentalanalysis and characterization, for the purpose of identifying,analyzing, and characterizing physicochemical properties, parameters,characteristics, and features.

Visual (Naked Eye) Observations of the Zero Valent Iron Composite:

The washing solution (1000 ml water and 200 ml acetone) of the zerovalent iron composite contained no visually noticeable dissolved ironor/and vitamin B₁₂. Each of these chemical species are visuallynoticeable in dissolved forms even at low concentrations, for example,B₁₂ is clearly visible at concentrations as low as about 1 micro-molar(μM).

The zero valent iron composite appeared physically different than theinitial ‘clean’ (pre-treated, pre-reacted) powdered diatomite used inthe synthesis reaction.

The zero valent iron composite exhibited magnetic properties, typicalfor iron, but not for powdered diatomite. For example, when a magnet wasbrought into direct contact with dry zero valent iron composite,particles of the dry zero valent iron composite stuck to the magnet,clearly indicative of the iron content in the dry zero valent ironcomposite. By strong contrast, as was obviously expected, the clean(pre-treated, pre-reacted) powdered diatomite did not stick to themagnet.

Upon exposure to air at room temperature, the color of the zero valentiron composite changed from black to gray, then to dark green, andfinally to rusty brown, indicative of oxidation of the nanometer sizedzero valent iron particles incorporated on or/and in the powdereddiatomite matrix. The time frame for the oxidative color change fromblack to brown was of the order of several hours to days. By contrast,when a separate sample of only nanometer sized zero valent ironparticles (which were not part of a composite) in powder form is exposedto air, the oxidation process is immediate, accompanied by release of arelatively large amount of heat and consequent increase of temperature,confirmation of the well known pyrophoric behavior of nanometer sizedzero valent iron particles.

It was also particularly observed that initiation and extent of theoxidation process took a significantly longer period of time for thezero valent iron composite including the vitamin B₁₂ electron transfermediator, compared to a similarly synthesized zero valent iron compositewithout any electron transfer mediator, leading to the hypothesis thatthe presence of an electron transfer mediator, at least in the case ofvitamin B₁₂, in the zero valent iron composite, inhibited and sloweddown initiation and extent of the oxidation process. This hypothesis isparticularly relevant when using a zero valent metal composite, such asthe zero valent iron composite described and exemplified herein, forcatalytically treating contaminated water, since, in most actualapplications, the zero valent metal composite needs to function as acatalyst in an air environment.

Upon exposing contaminated water having halogenated organic compounds tothe zero valent iron composite in batch mode experiments (describedhereinbelow, in Example 6), there was noticeable evolution of gas,indicative of hydrogen being released as a result of one or morecatalytic redox reactions taking place.

Scanning Electron Microscopy (SEM) of the Zero Valent Iron Composite:

Scanning electron microscopy (SEM) measurements were made on selectedsamples of a ‘clean’ (pre-treated, pre-reacted) powdered diatomite, ofthe zero valent iron composite, and of a ‘comparative reference’ zerovalent iron composite not including the vitamin B₁₂ electron transfermediator.

FIGS. 1A and 1B are SEM photographs showing a 5 μm and 1 μm scale,respectively, of a portion of the ‘clean’ (pre-treated, pre-reacted)powdered diatomite used for manufacturing (synthesizing) the differentspecific embodiments of the zero valent iron composite, as describedhereinabove and exemplified in Examples 1, 2, and 3. FIGS. 2A and 2B areSEM photographs showing a 5 μm and 1 μm scale, respectively, of aportion of the (dry) zero valent iron composite manufactured(synthesized) as described hereinabove and exemplified in Example 1,composed of a powdered diatomite matrix on or/and in which isincorporated zero valent iron particles (for example, which appear aswhite colored relatively small circularly shaped spots, as pointed to bythe paired arrows) having a size in a range of between about 1 nm andabout 1000 nm and vitamin B₁₂ (metallocorrin complex type ofporphyrinogenic organometallic complex, as the exemplary electrontransfer mediator).

Comparison of the SEM photographs of FIGS. 2A and 2B with those of FIGS.1A and 1B, respectively, clearly showed that nanometer sized zero valentiron particles were incorporated on or/and in (dispersed throughout,supported by, and adhered in a chemical bonding manner to) the powdereddiatomite matrix of the zero valent iron composite. Elemental analysisof the surface layer of a portion of the zero valent iron composite,encompassing the powdered diatomite matrix and a plurality of thenanometer sized zero valent iron particles, indicated the presence ofsilica and iron. The SEM instrument was unable to resolve elementalanalysis at the size scale of individual nanometer sized zero valentiron particles observed in the SEM photographs.

FIG. 3 is a SEM photograph showing a 5 μm scale of a portion of anexemplary ‘comparative reference’ zero valent metal composite (withoutan electron transfer mediator), being a (dry) zero valent iron compositemanufactured (synthesized) ‘similar’ to that as described hereinaboveand exemplified in Example 1, composed of a powdered diatomite matrix onor/and in which is incorporated zero valent iron particles (for example,which appear as white colored relatively large irregularly shapedaggregates, as pointed to by the arrows) having an average size largerthan about 600 nm, without an electron transfer mediator, for serving asan exemplary reference zero valent metal composite when compared to theexemplary zero valent metal composite of the present invention whichappears in the SEM photographs of FIGS. 2A and 2B. Comparison of the SEMphotographs of FIGS. 2A and 2B with that of FIG. 3 clearly shows thesignificantly different geometrical shape or form of the zero valentiron particles, in particular, relatively small circularly shapedparticles (FIGS. 2A and 2B) vs. relatively large irregularly shapedaggregates (FIG. 3), according to the presence or absence, respectively,of an electron transfer mediator (for example, vitamin B₁₂) incorporatedon or/and in the powdered diatomite matrix of the zero valent ironcomposite.

These exemplary empirical observations based on comparisons of the SEMphotographs of FIGS. 2A and 2B with those of FIGS. 1A, 1B, and 3,convincingly support several main general inventive aspects of thepresent invention. Firstly,

wherein the presence of an electron transfer mediator (for example,vitamin B₁₂) incorporated on or/and in the powdered diatomite matrix ofthe zero valent metal composite, significantly influences thegeometrical shape or form of the zero valent metal particlesadditionally incorporated on or/and in the powdered diatomite matrix ofthe zero valent metal composite. Secondly, wherein the presence of anelectron transfer mediator (for example, vitamin B₁₂) during themanufacturing (synthesizing) of the zero valent metal composite,significantly influences the geometrical shape or form of the zerovalent metal particles in the manufactured (synthesized) zero valentmetal composite. Thirdly, wherein, apparently, the presence of anelectron transfer mediator (for example, vitamin B₁₂) incorporated onor/and in the powdered diatomite matrix of the zero valent metalcomposite, significantly influences the physicochemical properties,characteristics, and behavior, of the zero valent metal particlesadditionally incorporated on or/and in the powdered diatomite matrix ofthe zero valent metal composite, in particular, and therefore, of thezero valent metal composite, in general. This includes, for example,with respect to applications involving the use of the zero valent metalcomposite for treating contaminated water.

Transmission Electron Microscopy (TEM) of the Zero Valent IronComposite:

Transmission electron microscopy (TEM) measurements were made onselected samples of the zero valent iron composite, manufactured(synthesized) as described hereinabove and exemplified in Example 1, andwhich appears in the SEM photographs of FIGS. 2A and 2B.

Preparation of each TEM sample consisted of making an aqueous suspensionof the zero valent iron composite and placing an aliquot of thesuspension in a vial, manually shaking the vial for a few minutes, andthen allowing the zero valent iron composite to settle throughout thelength of a vertically positioned graduated column, for a period ofabout 30 min. Following the settling period, a relatively simple sizeseparation of the suspension was performed by removing small volumesamples of the suspended zero valent iron composite at different heightsalong the column. Each volume sample was then stored at room conditionsfor a period of several days prior to performing the TEM measurements.During preparation of each TEM sample of the aqueous suspension of thezero valent iron composite, activity of the zero valent iron compositewas observed in the form of evolution of hydrogen gas bubbles, clearlyindicating dissociation of the water, along with consequent oxidation ofthe nanometer sized zero valent iron particles in the composite.

FIGS. 9A and 9B are TEM photographs showing a 500 nm and 100 nm scale,respectively, of a volume sample, removed from near the bottom of thecolumn, of the aqueous suspension (stored for several days at roomconditions) of the zero valent iron composite. In FIG. 9A, at the lowermagnification (500 nm scale), two distinct types of regions wereobserved throughout the entire TEM photograph—a plurality of separatesmall dark regions corresponding to the zero valent iron particles,which were dispersed throughout the background of a single contiguouslarger lighter region corresponding to the powdered diatomite matrixsurface. The TEM analysis was limited to TEM samples of the aqueoussuspension having a thickness of less than about 50 nm, which allowedpenetration of the electron beam. Therefore, additional TEM photographswere taken at a higher magnification (100 nm scale) while focusing onthe edges of the pores and shell of the powdered diatomite matrixsurface observed in the TEM samples of FIG. 9A, as shown in FIG. 9B. InFIG. 9B the same two distinct types of regions were observed throughoutthe entire TEM photograph. The average diameter of the small darkregions corresponding to the zero valent iron particles was evaluated tobe about 10 nm.

For the objective of further investigating and analyzing the aqueoussuspension sample of the zero valent iron composite which appeared inthe TEM photographs of FIGS. 9A and 9B, additional TEM measurements athigher resolutions of 5 nm and 10 nm scales were made on the aqueoussuspension sample of the zero valent iron composite, as shown in the TEMphotographs of FIGS. 10A and 10B. In the TEM photographs of FIGS. 10Aand 10B, at these higher resolutions, crystalline structures (as pointedto by the arrows) were observed in both of the preceding identified anddescribed two distinct types of regions (separate small dark regionscorresponding to the zero valent iron particles, and single contiguouslarger lighter region corresponding to the powdered diatomite matrixsurface) of the zero valent iron composite.

Two distinctly different spacings or distances (especially noticed inFIG. 10A) between the layers of the crystalline structures were measuredand evaluated from the TEM images and their FFT transforms as beingabout 2.9 Å and about 4.9 Å. These results lead to the hypothesis thattwo different types of crystalline structures of the zero valent ironparticles were incorporated on or/and in the powdered diatomite matrixof the zero valent iron composite.

Quantitative elemental analysis was performed, via the TEM apparatus, onthe aqueous suspension sample of the zero valent iron composite. Theresults, shown in the following table, indicated the presence of iron,silicon, oxygen, and to a lesser extent, carbon, cobalt, aluminum, andzinc. The presence of copper was attributed to the metal TEM sampleholder grid.

Element Atomic % O 55.6 Al 0.3 Si 19.9 Fe 22.6 Co 0.8 Zn 0.8 Total 100

Considering that all of the Si was in the form of SiO₂, as the powdereddiatomite matrix, then 15.8% of the oxygen remained for being complexedwith other species of the zero valent iron composite. This amount of theoxygen does not account for complete oxidation of all of the measuredquantity of the iron. Hence, it was concluded that at least a fractionof the iron remained in the active elemental zero valent metal statefollowing several days of exposure of the nanometer sized zero valentiron particles to water in the aqueous suspension sample of the zerovalent iron composite. These results lead to the conclusion that thenanometer sized zero valent iron particles remained in the reduced, andtherefore, catalytically active, form, even following exposure to waterfor several days. This conclusion is highly relevant with respect toapplication of the zero valent iron composite for treating contaminatedwater, wherein exposure (residence) time of the zero valent ironcomposite is typically at least several days. During the exposure(residence) time it is important for the zero valent iron particles toremain in the reduced, and therefore, catalytically active, form,thereby enabling the various heterogeneous catalytic reaction processesto take place for catalytically treating contaminated surface water, tothereby decrease concentration of at least one of the contaminants inthe contaminated surface water.

Another TEM sample was prepared from the dry (non-suspended),anaerobically stored, and non-separated zero valent iron composite thatwas used for making the TEM measurements shown in FIGS. 9A, 9B, 10A, and10B. The zero valent iron composite sample was maintained underanaerobic conditions until TEM sample preparation. TEM measurements ofthe zero valent iron composite sample were carried out within two hoursfrom the time of preparing the TEM sample. In this case, it was observedthat the zero valent iron particles were relatively small circularlyshaped with a diameter up to about 50 nm.

The crystalline structure of the zero valent iron particles could not bedirectly measured since the resolution of the TEM instrument (2.6 Å) waslarger than the layer spacing characteristic of elemental iron. However,an indirect measurement of the layer spacing was obtained by performingan electron diffraction analysis using the TEM. The FFT signal of theelectron diffraction analysis corresponded to a characteristic layerspacing of about 1.9 Å.

Quantitative elemental analysis was performed, via the TEM apparatus, onthe sample of the zero valent iron composite, and the results obtainedare shown in the following table:

Element Atomic % O 44.6 Al 0.7 Si 26.6 Fe 25.9 Co 1.1 Zn 1.0 Total 100

This analysis clearly indicated that the amount of oxygen observed inthe zero valent iron composite was not sufficient to account for thestoichiometry of regular silica (SiO₂), for the zero valent ironcomposite being maintained under anaerobic conditions. This lead to theconclusion that there was some reduction, (for example, probably by thereducing agent) during the synthesis of the original powdered diatomitematrix. Based on this lower than expected level of oxygen, lead to thehypothesis that either as part of, or in addition to, mechanism(s) forincorporating of the zero valent iron particles in the metallic (zerovalent) elemental iron state into the powdered diatomite (silica)surface, another mechanism takes place which involves reduction of theoriginal powdered diatomite matrix involving some kind of yetundetermined physicochemical bonding.

FTIR Spectroscopy and XRD of the Zero Valent Iron Composite:

FTIR spectroscopy and XRD measurements were made on selected samples ofthe ‘clean’ (pre-treated, pre-reacted) powdered diatomite used formanufacturing (synthesizing) the different specific embodiments of azero valent iron composite, as described hereinabove and exemplified inExamples 1, 2, and 3, and were made on selected samples of the differentspecific embodiments (without vermiculite) of the zero valent ironcomposite manufactured (synthesized) as described hereinabove andexemplified in Example 1, in accordance with the present invention.

The FTIR (400-2000 cm⁻¹; sample in a KBr pellet) and XRD (2θ=15-85)measurements indicated that the powdered diatomite in the zero valentiron composite retained its original mineralogical composition, whichconsists mostly of opal, crystobalite, and quartz. Regarding the FTIRspectra, since absorption peaks for Fe and Si minerals are usually below400 cm⁻¹, they were not observed in the spectral range of measurement.Main peaks associated with the (clean or zero valent iron composite)powdered diatomite, in decreasing order of their amplitudes, were at1093 cm⁻¹, 474 cm⁻¹, 793 cm⁻¹, and 620 cm⁻¹. Regarding the XRD scans,when compared to that of the clean powdered diatomite, the XRD scan ofthe powdered diatomite in the zero valent iron composite included anadditional peak at 2θ=47.3, indicating the probability that a new typeof crystal structure or species was formed on the diatomite powdermatrix during the synthesis of the zero valent iron composite.

Example 5 Measurement of Permeability, k, of a Zero Valent MetalComposite

Permeability, k, measurements were made on selected samples of two ofthe different specific embodiments (without vermiculite, and includingvermiculite) of a zero valent iron composite manufactured (synthesized)as described hereinabove and exemplified in Examples 1 and 3,respectively, in accordance with the present invention. Values obtainedfrom these measurements were compared to ranges of known values ofpermeability, k, of several common porous materials, at comparablemeasurement conditions.

The permeability measurements were made using a standard falling headpermeameter apparatus, as described in detail in the art [e.g., 56, 57].Each synthesized zero valent iron composite, of Examples 1 and 3, waspacked into a cylindrical column (permeameter) apparatus having a lengthof about 20 cm and a diameter of 1 cm. For these permeabilitymeasurements, the scale of measurement was on the order of centimeters.

Values obtained for permeability, k, of the zero valent iron compositesof Examples 1 and 3, being composed of a powdered diatomite matrix onor/and in which is incorporated zero valent iron particles having a sizein a range of between about 1 nm and about 1000 nm and vitamin B₁₂,(without vermiculite, and including vermiculite, respectively) were8.7×10⁻⁹ cm², and 1.48×10⁻⁸ cm², respectively.

Apparently, the presence of vermiculite in the zero valent ironcomposite caused a slight increase in the linear velocity of the liquidphase water flowing through the zero valent iron composite, resulting ina slight increase in the permeability, k, of the zero valent ironcomposite including vermiculite, compared to a similar zero valent ironcomposite, but manufactured without vermiculite.

Ranges of known values of permeability, k, of several common porousmaterials, at comparable measurement conditions, are as follows (from[57]):

Coarse gravels 10⁻⁴-10⁻⁵ cm² Sands and gravels 10⁻⁵-10⁻⁸ cm² Fine sands,silt, loess 10⁻⁸-10⁻¹² cm² Clay, shale, glacial till 10⁻¹²-10⁻¹⁶ cm²Sandstone 10⁻⁷-10⁻¹³ cm² Limestone 10⁻⁸-10⁻¹² cm² Weathered chalk10⁻⁶-10⁻⁸ cm²

Comparison of the values obtained for permeability, k, of the zerovalent iron composites of Examples 1 and 3, to the above list of rangesof known values of permeability, k, of several common porous materials,at comparable measurement conditions, shows that values of permeability,k, for the zero valent iron composites of Examples 1 and 3, are of aboutthe same or greater order of magnitude compared to that for most of theabove listed common porous materials.

Examples 6-9 Catalytically Treating Contaminated Water Using a ZeroValent Metal Composite

In each of the following Examples 6-9, a series of heterogeneouscatalytic type batch mode experiments (i.e., control or test material,contaminated water, and, reaction (degradation, transformation, or/andconverted) products, maintained in a batch type closed vial-reactor) wasperformed in order to measure and analyze catalytic treatment of asample of contaminated water, separately using different specificembodiments of the hereinabove illustratively described zero valentmetal composite.

In each of Examples 6-9, the contaminated water initially included anexemplary water contaminant characterized as being composed of anorganic specie or of an inorganic specie. In each of Examples 6, 7, and8, the initial exemplary water contaminant was a halogenated organiccompound, i.e., carbon tetrachloride (CT) [Example 6],tetrachloroethylene (PCE) [Example 7], and tribromoneopentlyalcohol(TBNPA) [Example 8]. In Example 10, the initial exemplary watercontaminant was a charged (cationic) form of a transition metal element,i.e., hexavalent chromium (chromium (VI) cation [Cr⁺⁶]), originatingfrom the inorganic compound potassium dichromate [K₂Cr₂O₇].

In each of Examples 6-9, (the same) two different specific embodimentsof a zero valent metal composite, separately, were used forcatalytically treating the contaminated water.

The first specific embodiment of the zero valent metal composite was thezero valent iron (ZVI) composite manufactured (synthesized) as describedhereinabove and exemplified in Example 1, being composed of a powdereddiatomite matrix incorporated with zero valent iron particles having asize in a range of between about 1 nm and about 1000 nm and vitamin B₁₂,(without vermiculite).

The second specific embodiment of the zero valent metal composite wasthe zero valent iron (ZVI) composite manufactured (synthesized) asdescribed hereinabove and exemplified in Example 3, in accordance withthe hereinabove described second exemplary alternative preferredembodiment of the manufacturing method (with optional addition ofvermiculite), i.e., including the alternative optional procedure ofadding vermiculite to the collected zero valent metal composite (absentof vermiculite), for forming the zero valent metal composite (includingvermiculite). Accordingly, the second specific embodiment of the zerovalent iron (ZVI) composite was composed of a powdered diatomite matrixincorporated with zero valent iron particles having a size in a range ofbetween about 1 nm and about 1000 nm and vitamin B₁₂, and additionallyincluding vermiculite.

Materials and Experimental Methods

Water:

Distilled deionized filtered water, generated by a Milli-Q waterpurification system, was exclusively used throughout.

Water Contaminants, and Contaminated Water Stock Solutions Thereof:

Example 6

Water contaminant—carbon tetrachloride (CT), 99%, from Frutarom Ltd.,Israel. Contaminated water stock solution—carbon tetrachloride (CT), 50mg/l (50 ppm).

Example 7

Water contaminant—tetrachloroethylene (PCE), 99%, from Frutarom Ltd.,Israel. Contaminated water stock solution—tetrachloroethylene (PCE), 50mg/l (50 ppm). Trichloroethylene (TCE), 98%, from Bio Lab Ltd., Israel,for the gas chromatographic analytical procedure.

Example 8

Water contaminant—tribromoneopentlyalcohol (TBNPA), 99%, from DSBG Ltd.,Israel. Contaminated water stock solution—tribromoneopentlyalcohol(TBNPA), 50 mg/l (50 ppm).

Example 9

Water contaminant—hexavalent chromium (chromium (VI) cation [Cr⁺⁶]),originating from potassium dichromate [K₂Cr₂O₇], 99.5%, from Fluka.Contaminated water stock solution—hexavalent chromium (chromium (VI)cation [Cr⁺⁶]), 10 mg/l (10 ppm).

Zero Valent Metal Composites (Each of Examples 6-9):

First specific embodiment—anaerobically stored, dry zero valent iron(ZVI) composite, from hereinabove Example 1, composed of a powdereddiatomite matrix incorporated with zero valent iron particles having asize in a range of between about 1 nm and about 1000 nm and vitamin B₁₂,(without vermiculite).

Second specific embodiment—anaerobically stored, dry zero valent iron(ZVI) composite, from hereinabove Example 3, composed of a powdereddiatomite matrix incorporated with zero valent iron particles having asize in a range of between about 1 nm and about 1000 nm and vitamin B₁₂,and additionally including vermiculite.

In each of the first and second specific embodiments of the zero valentiron (ZVI) composite, the powdered diatomite matrix particles had aparticle size in a range of between about 1 micron and about 150microns, and a pore size in a range of between about 1 nm and about 5000nm; zero valent iron particle concentration was about 7.7% (weight(mass) percent); and vitamin B₁₂ electron transfer mediatorconcentration was about 0.038% (weight (mass) percent). In the secondspecific embodiment, the additionally included vermiculite had a piecesize in a range of between about 0.01 mm and about 20.0 mm, and aconcentration of about 50% (weight (mass) percent).

Extraction Solvents (or GC Analysis), and Reagents (for ColorimetricAnalysis):

In Examples 6-8, the following extraction solvents were used forperforming a (liquid-liquid) extraction and centrifuge separationprocedure of the contents of each batch mode reactor, for preparing a GCsample for performing the GC analytical procedure. Example 6—hexane,99+%, from Aldrich, Germany. Example 7-cyclohexane, 99.5%, from AldrichLtd., Israel. Example 8—toluene, 99.5%, from Frutarom Ltd., Israel.

In Example 9, the following reagents were used for performing thecalorimetric (photometric) analytical procedure. Diphenylcarbazide, 97%,from Fluka, Austria; sulfuric acid [H₂SO₄], 98%, from BDH, England; andreagent grade water-Milli-Q distilled deionized filtered water.

Heterogeneous Catalytic Batch Mode Reactor (as an Exemplary In-Situ orEx-Situ Unit) (Each of Examples 6-9):

For each heterogeneous catalytic type batch mode reactor, a 40milliliter (0.4 liter) glass vial was used at room temperature (betweenabout 20° C. and about 25° C.) and atmospheric pressure. Contents of theglass vial (batch reactor) were mixed by securing the glass vial onto anorbital shaker (model TS-600, from MRC, Israel) having automatic(mixing) speed control.

Experimental Setup, Procedures, and Reaction Conditions (Each ofExamples 6-9)

For each of Examples 6-9, the experimental setup consisted of tworeplicate sets of the same number of separate ‘control’ and ‘test’ batchmode reactors (i.e., 40 ml glass vials) containing control or testmaterials, described and prepared as follows:

Control-1: Contaminated Water (Example 6 only): contaminated wateralone.

A volume, 50 milliliters, of the carbon tetrachloride (CT), 50 mg/l (50ppm), contaminated water stock solution was added to an empty 40 mlglass vial (batch mode reactor).

Control-2: Diatomite: contaminated water exposed to controlmaterial—clean (pre-treated, pre-reacted) powdered diatomite matrix.This control was used for assessing the possibility of contaminantadsorption onto the clean powdered diatomite matrix, being the same asthat included in the zero valent iron composite used in the belowindicated two test batch mode reactors.

A weight, 2.5 grams (Example 6), 1.5 grams (Examples 7, 8), or 0.25 gram(Example 9), of the powdered diatomite, was added to an empty glass vial(batch mode reactor). To that was added a volume, 50 milliliters(Example 6), 15 milliliters (Examples 7, 8), or 25 milliliters (Example9), of the respective above prepared contaminated water stock solution.

Control-3: Diatomite+Fe⁰ (Example 6 only): contaminated water exposed tocontrol material-powdered diatomite matrix incorporated with only zerovalent iron particles having a size in a range of between about 1 nm andabout 1000 nm, being the same components included in the zero valentiron composite used in the below indicated two test batch mode reactors.

A weight, 2.5 grams, of the powdered diatomite incorporated with thezero valent iron particles was added to an empty glass vial (batch modereactor). To that was added a volume, 50 milliliters, of the carbontetrachloride (CT), 50 mg/l (50 ppm), contaminated water stock solution.

Test-1: Diatomite+Fe⁰+B₁₂: contaminated water exposed to testmaterial—above described first specific embodiment of the zero valentiron (ZVI) composite (without vermiculite) (from Example 1).

A weight, 2.5 grams (Example 6), 1.5 grams (Examples 7, 8), or 0.25 gram(Example 9), of the zero valent iron (ZVI) composite (withoutvermiculite), was added to an empty glass vial (batch mode reactor). Tothat was added a volume, 50 milliliters (Example 6), 15 milliliters(Examples 7, 8), or 25 milliliters (Example 9), of the respective aboveprepared contaminated water stock solution.

Test-2: Diatomite+Fe⁰+B₁₂+Vermiculite: contaminated water exposed totest material—above described second specific embodiment of the zerovalent iron (ZVI) composite (with vermiculite) (from Example 3).

A weight, 2.5 grams (Example 6), 1.5 grams (Examples 7, 8), or 0.25 gram(Example 10), of the zero valent iron (ZVI) composite (withvermiculite), was added to an empty glass vial (batch mode reactor). Tothat was added a volume, 50 milliliters (Example 6), 15 milliliters(Examples 7, 8), or 25 milliliters (Example 9), of the respective aboveprepared contaminated water stock solution.

Following preparation of each of the above ‘control’ and ‘test’ batchmode reactors, the contents in each glass vial (batch mode reactor) werecontinuously mixed by securing the glass vial onto the orbital shakerset at a mixing speed of 150 rpm. Such mixing of the batch mode reactorswas maintained for the entire extent of time or duration of reaction,thereby maximizing exposure of the water contaminants in thecontaminated water to the control and test materials.

The heterogeneous catalytic type batch mode water treatment experimentswere performed at room temperature (between about 20° C. and about 25°C.) and atmospheric pressure, for the entire extent of time or durationof reaction. For each control and test batch mode reactor, at periodictime intervals, measurements, and analysis thereof, were made on thedegradation rate (kinetics) of the respective water contaminant, i.e.,carbon tetrachloride (CT) [Example 6], tetrachloroethylene (PCE)[Example 7], tribromoneopentlyalcohol (TBNPA) [Example 8], or hexavalentchromium (chromium (VI) cation [Cr⁺⁶]) [Example 9], in the contaminatedwater, using the below described gas chromatography (GC) or colorimetric(photometric) analytical procedures.

Analytical Procedures (GC, Colorimetry):

Concentration over time, of the water contaminant, and reaction (i.e.,degradation, transformation, or/and conversion) products (i.e.,dechlorination product(s)) thereof, of each batch mode reactor in eachset of control and test batch mode reactors, was measured using gaschromatography (GC) [Examples 6-8] or colorimetry (photometry) [Example9].

At the end of each pre-determined extent of time or duration ofreaction, for each set of the two replicate sets of the separate‘control’ and ‘test’ batch mode reactors (i.e., 40 ml glass vials)containing the reacting control or test materials under the above mixingconditions, and for each type (i.e., control-1, control-2, control-3,test-1, test-2) of control and test batch mode reactor, the contents oftwo identical batch mode reactors (glass vials) were used (‘sacrificed’)for GC analysis (Examples 6-8) or calorimetric (photometric) analysis(Example 9). Mixing of the contents of the remaining control and testbatch mode reactors (glass vials) was maintained via the orbital shaker,until reaching the end of the next pre-determined extent of time orduration of reaction, at which time GC or calorimetric analysis of thebatch mode reactor contents was again performed. The preceding procedurewas continuously repeated until reaching the end of the finalpre-determined extent of time or duration of reaction for each set ofcontrol and test batch mode reactors.

Gas Chromatography:

For Examples 6-8, in accordance with the preceding described analyticalprocedure for measuring the concentration over time, of the watercontaminant, and reaction (i.e., degradation, transformation, or/andconversion) products (i.e., dechlorination product(s)) thereof, of eachbatch mode reactor in each set of control and test batch mode reactors,the contents of each batch mode reactor (glass vial) were used(‘sacrificed’) in a (liquid-liquid) extraction and centrifuge separationprocedure for preparing a GC sample for performing the GC measurementsand analysis.

In Example 6, for the GC sample preparation procedure, 20 milliliters ofwater were taken from each batch mode reactor (glass vial), and theorganic species were extracted therefrom using 4 milliliters of anextraction solvent (hexane), under conditions of shaking at a speed of150 rpm, followed by centrifuge separation. In Examples 7, and 8, forthe GC sample preparation procedure, 15 milliliters of water were takenfrom each batch mode reactor (glass vial), and the organic species wereextracted therefrom using 3 milliliters of an extraction solvent(cyclohexane [Example 7], toluene [Example 8]), under conditions ofshaking at a speed of 150 rpm, followed by centrifuge separation.

In Examples 6-8, an HP 5890 GC instrument, equipped with an electroncapture detector (ECD), was used for sample analysis. In Example 6, theGC column was a J&W Scientific, DB VRX capillary column, 30 meterlength, 0.32 mm inner diameter, and 1.8 micron film layer thickness. InExamples 7, and 8, the GC column was a J&W Scientific, DB5 ms capillarycolumn, 25 meter length, 0.25 mm inner diameter, and 0.25 micron filmlayer thickness. In each example, the GC carrier gas was nitrogen (N₂),at a flow rate of 1 ml per minute. Details regarding the GC temperatureprogram, and, injector and detector temperatures, used in each ofExamples 6-8 are as follows:

Example 6 Carbon Tetrachloride (CT) Water Contaminant

GC temperature program—60° C. for 1.5 minutes; ramp at 5° C. per minuteto 80° C.; ramp at 15° C. per minute to 200° C.; hold for 1 minute.Injector and detector temperatures were maintained at 220° C., and 300°C., respectively.

Example 7 Tetrachloroethylene (PCE) Water Contaminant

GC temperature program—50° C. for 2 minutes; temperature ramp of 17° C.per minute to 190° C.; hold for 1 minute. Injector and detectortemperatures were maintained at 190° C., and 300° C., respectively.

Example 8 Tribromoneopentlyalcohol (TBNPA) Water Contaminant

GC temperature program—200° C. for 1 minute; temperature ramp of 10° C.per minute to 250° C.; hold for 4 minutes. Injector and detectortemperatures were maintained at 220° C., and 300° C., respectively.

For Examples 6-8, while performing the GC analytical procedure, GC areacount units, being directly proportional to the concentration of theindicated halogenated organic compound water contaminant in the batchmode reactor at the end of the indicated extent of time or duration ofreaction, were recorded, and subsequently used for analyzing theexperimental data, as presented in tabulated form (i.e., Tables 2-4,below).

Colorimetry (Photometry):

For Example 9, in accordance with the preceding described analyticalprocedure for measuring the concentration over time, of the watercontaminant [i.e., hexavalent chromium (chromium (VI) cation [Cr⁺⁶])],and reaction (i.e., degradation, transformation, or/and conversion)product (i.e., Cr⁺³) thereof, of each batch mode reactor in each set ofcontrol and test batch mode reactors, the contents of each batch modereactor (glass vial) were sampled (without an extraction procedure), intriplicate, for performing the colorimetric (photometric) measurementsand analysis.

The calorimetric (photometric) procedure used corresponds to USEnvironmental Protection Agency (EPA) Method 7169A: “ColorimetricDetermination Of Hexavalent Chromium” [58]. In accordance with thismethod, hexavalent chromium (chromium (VI) cation [Cr⁺⁶]) dissolved inaqueous solution, in the absence of interfering amounts of substances,such as molybdenum, vanadium, or/and mercury, may be calorimetrically(photometrically) determined by reaction with diphenylcarbazide in acidsolution. A red-violet color of unknown composition is produced. Thecalorimetric (photometric) reaction is highly sensitive. For example,absorbancy index per gram atom of hexavalent chromium is about 40,000measured at a wavelength of 540 nm. Addition of an excess amount ofdiphenylcarbazide yields the red-violet colored reaction product, andits absorbance is colorimetrically (photometrically) measurable at 540nm.

In Example 9, for the colorimetric (photometric) procedure, 95 ml ofwater were taken from each batch mode reactor (glass vial), andtransferred to a 100 ml volumetric flask. A volume, 2 ml, ofdiphenylcarbazide solution was added to the flask, along with mixing theflask contents. Sulfuric acid [H₂SO₄] solution was then added to theflask, for obtaining a pH of 2±0.5. The contents of the flask were thendiluted to 100 ml with reagent grade water, and allowed to stand for atime of between about 5 minutes and about 10 minutes in order to achievefull color development. An appropriate volumetric sample was taken fromthe solution in the flask, and transferred to a 1 centimeter absorptioncell of a calorimeter (photometer) instrument (Varian, Cary 100BioUV-Visible spectrometer). Absorbance of the solution was measured at 540nm.

As part of the colorimetric (photometric) procedure, reagent grade waterwas used as a reference. Sample absorbance readings were corrected bysubtracting the absorbance of a blank used in the procedure. An aliquotof the sample containing all reagents, except diphenylcarbazide, wasprepared and used to correct the sample for turbidity (i.e., a turbidityblank).

For Example 9, while performing the colorimetric (photometric)procedure, absorbance units, being directly proportional to theconcentration of the hexavalent chromium (chromium (VI) cation [Cr⁺⁶])water contaminant in the batch mode reactor at the end of the indicatedextent of time or duration of reaction, were recorded, and subsequentlyused for analyzing the experimental data, as presented in tabulated form(i.e., Table 5, below).

EXPERIMENTAL RESULTS Example 6 Catalytically Treating Contaminated WaterUsing a Zero Valent Metal Composite: Carbon Tetrachloride (CT) WaterContaminant, Zero Valent Iron Composite

The results obtained for Example 6 are presented in the followingTable 1. Table 1 lists concentration (in terms of GC area count units)of the (carbon tetrachloride (CT)) water contaminant remaining in eachtype of control and test batch mode reactor, measured at the end of twoextents of time or duration of reaction, i.e., after 2 days, and after 2weeks.

TABLE 1 Concentration of carbon tetrachloride (CT) (in terms of(absolute) area count units) remaining in control and test batch modereactors, measured after 2 days, and after 2 weeks. Batch mode reactorCT concentration After 2 days Control - 1: Contaminated Water 2906.9 ±58.5  Control - 2: Diatomite 2838.0 ± 4.9   Control - 3: Diatomite + Fe⁰46.5 ± 5.1  Test - 1: Diatomite + Fe⁰ + B₁₂ 0.0 ± 0.0 Test - 2:Diatomite + Fe⁰ + B₁₂ + Vermic. 0.0 ± 0.0 After 2 weeks Control - 1:Contaminated Water 2984.4 ± 193.6  Control - 2: Diatomite 2596.8 ± 99.3 Control - 3: Diatomite + Fe⁰ 0.0 ± 0.0 Test - 1: Diatomite + Fe⁰ + B₁₂0.0 ± 0.0 Test - 2: Diatomite + Fe⁰ + B₁₂ + Vermic. 0.0 ± 0.0

The results listed in Table 1 show that after only 2 days of exposure,each test material, Test-1 (Diatomite+Fe⁰+B₁₂) and Test-2(Diatomite+Fe⁰+B₁₂+Vermiculite), catalytically completely eliminated, ordecreased to zero, the concentration of the water contaminant (carbontetrachloride (CT)). By strong contrast, for the same 2 day time period,the Control-2 material (Diatomite) decreased the concentration of thewater contaminant by a significantly smaller amount, of only about 2%.For the same 2 day exposure time period, the Control-3 material(Diatomite+Fe⁰) catalytically decreased the concentration of the watercontaminant by about 98%.

After 2 weeks of exposure, each of the Test-1 and Test-2 materials, andthe Control-3 material, catalytically completely eliminated, ordecreased to zero, the concentration of the water contaminant. Similarto the results of after 2 days, for the same 2 week time period, theControl-2 material decreased the concentration of the water contaminantby a significantly smaller amount, of only about 13%.

Example 7 Catalytically Treating Contaminated Water Using a Zero ValentMetal Composite: Tetrachloroethylene (PCE) [and Trichloroethylene (TCE)]Water Contaminants, Zero Valent Iron Composite

The results obtained for Example 7 are presented in the following Tables2 and 3. Table 2 lists concentration (normalized relative to controlwith clean diatomite) of the tetrachloroethylene (PCE) water contaminantremaining in each type of control and test batch mode reactor,periodically measured at the end of several extents of time or durationof reaction, within a range of between 1 hour and 160 hours.

TABLE 2 Concentration of tetrachloroethene (PCE) (normalized relative tothe control with clean diatomite) remaining in control and test batchmode reactors, periodically measured in a range of 1-160 hours.treatment Test - 1: Test - 2: time Diatomite + Diatomite + Fe⁰ +Control - 2: (hours) Fe⁰ + B₁₂ B₁₂ + Vermiculite Diatomite 1 92 98 1005.5 92 88 100 22 40 50 100 44 20 42 100 66 5 22 100 93 1 12 100 160 1 1100

The results listed in Table 2 show that the degradation reaction isimmediate and after only less than 24 hrs of exposure, each testmaterial, Test —I (Diatomite+Fe⁰+B₁₂) and Test-2(Diatomite+Fe⁰+B₁₂+Vermiculite), catalytically eliminated, or decreasedto half, the concentration of the water contaminant (tetrachloroethylne(PCE)). After 93 and 160 hours for each of Test-1 and Test-2 materials,the concentration of the PCE is reduced to 1% of the initialconcentration. In strong contrast, for the same time period, theControl-2 material (Diatomite) decreased the concentration of the watercontaminant by a significantly smaller amount, which is incorporatedinto the data normalization calculation.

The results listed in Table 2 correspond to the measurements, andanalysis thereof, made on the degradation rate (kinetics) of thetetrachloroethylene (PCE) in the contaminated water. Sincetrichloroethylene (TCE) is produced as the main reaction (dechlorinationtype of degradation, transformation, or/and conversion) product duringcatalytic treatment of the tetrachloroethylene (PCE) contaminated water,therefore, measurements, and analysis thereof, were also made in termsof a ‘combined’ or ‘composite’ production and degradation rate(kinetics) of the trichloroethylene (TCE) in the contaminated water,effected by the zero valent iron composite, following exposing thetetrachloroethylene (PCE) contaminated water to the zero valent ironcomposite. These results are listed in the following Table 3. Table 3shows the ‘relative’ concentration of trichloroethylene (TCE),normalized relative to the maximum concentration of trichloroethylene(TCE), produced and degraded in control and test batch mode reactors,during tetrachloroethylene (PCE) treatment of Table 2, periodicallymeasured within a range of between 1 hour and 491 hours.

TABLE 3 Relative concentration of trichloroethylene (TCE) (normalizedrelative to the maximum concentration) produced and degraded in controland test batch mode reactors, during tetrachloroethylene (PCE) treatmentof Table 2, periodically measured in a range of 1-491 hours. treatmentTest - 1: Test - 2: time Diatomite + Diatomite + Fe⁰ + Control - 2:(hours) Fe⁰ + B₁₂ B₁₂ + Vermiculite Diatomite 1 7 11 2 5.5 24 15 2 22 6743 2 44 93 64 1 66 93 66 1 93 100 82 2 160 91 86 3 250 63 52 3 322 74 —2 345 59 57 2 491 52 49 4

It is thus seen that trichloroethylene is a substantial byproduct of thetetrachloethylene (TCE) degradation by Test-1 (Diatomite+Fe⁰+B₁₂) andTest-2 (Diatomite+Fe⁰+B₁₂+Vermiculite) materials only, and that itfurther decomposes after less than 3 weeks from the beginning of thetetrachloroethylene (PCE) reaction (i.e., TCE as a byproduct reaches amaximum concentration after about 93-160 hours, and then decreasesfurther).

Example 8 Catalytically Treating Contaminated Water Using a Zero ValentMetal Composite Tribromoneopentlyalcohol (TBNPA) Water Contaminant, ZeroValent Iron Composite

The results obtained for Example 8 are presented in the following Table4. Table 4 lists concentration (normalized relative to control withclean diatomite) of the tribromoneopentlyalcohol (TBNPA) watercontaminant remaining in each type of control and test batch modereactor, periodically measured at the end of several extents of time orduration of reaction, within a range of between 1 minute and 330minutes.

TABLE 4 Concentration of tribromoneopentlyalcohol (TBNPA) (normalizedrelative to the control with clean diatomite) remaining in control andtest batch mode reactors, periodically measured in a range of 1-330minutes. treatment Test - 1: Test - 2: time Diatomite + Diatomite +Fe⁰ + Control - 2: (minutes) Fe⁰ + B₁₂ B₁₂ + Vermiculite Diatomite 10 —67.4 100.0 25 59.1 54.2 100.0 40 49.5 54.5 100.0 60 48.7 42.8 100.0 9029.3 13.2 100.0 150 8.9 7.8 100.0 210 4.8 2.7 100.0 270 0.8 0.2 100.0330 0.2 0.1 100.0

The results listed in Table 4 show that the degradation reaction isimmediate and after only less than 330 min of exposure, each testmaterial, Test-1 (Diatomite+Fe⁰+B₁₂) and Test-2(Diatomite+Fe⁰+B₁₂+Vermiculite), catalytically eliminated, or decreasedto zero, the concentration of the water contaminant(tribromoneopentlyalcohol (TBNPA)). In strong contrast, for the sametime period, the Control-2 material (Diatomite) decreased theconcentration of the water contaminant by a significantly smalleramount, which is incorporated in the data normalization calculation.

Example 9 Catalytically Treating Contaminated Water Using a Zero ValentMetal Composite: Hexavalent Chromium (Chromium (VI) Cation [Cr⁺6]) WaterContaminant, Zero Valent Iron Composite

The results obtained for Example 9 are presented in the following Table5. Table 5 lists concentration (normalized relative to control withclean diatomite) of the water contaminant (hexavalent chromium (chromium(VI) cation [Cr⁺⁶]), originating from potassium dichromate [K₂Cr₂O₇]),remaining in each type of control and test batch mode reactor,periodically measured at the end of several extents of time or durationof reaction, within a range of between 0.25 minute and 0.58 minute.

TABLE 5 Concentration of hexavalent chromium (chromium (VI) cation[Cr⁺⁶]) (normalized relative to the control with clean diatomite)remaining in control and test batch mode reactors, periodically measuredin a range of 0.25-0.58 minute. treatment Test - 1: Test - 2: timeDiatomite + Diatomite + Fe⁰ + Control - 2: (minutes) Fe⁰ + B₁₂ B₁₂ +Vermiculite Diatomite 0.25 8.1 5.6 100.0 0.42 0.8 1.6 100.0 0.58 0.0 0.0100.0

The results listed in Table 5 show that the transformation or/andconversion of the hexavalent chromium (chromium (VI) cation [Cr⁺⁶])water contaminant to the trivalent chromium (chromium (III) cation[Cr⁺³]), being a non-hazardous form of chromium cation, is immediate andafter only less than 0.58 min of exposure. Each test material, Test-1(Diatomite+Fe⁰+B₁₂) and Test-2 (Diatomite+Fe⁰+B₁₂+Vermiculite),catalytically eliminated, or decreased to zero, the concentration of thehexavalent chromium (chromium (VI) cation [Cr⁺⁶]) water contaminant. Instrong contrast, for the same time period, the Control-2 material(Diatomite) decreased the concentration of the hexavalent chromium(chromium (VI) cation [Cr⁺⁶]) water contaminant water contaminant by asignificantly smaller amount, which is incorporated in the datanormalization calculation.

Thus, based on, in addition to, or a consequence of, the above describedaspects of novelty and inventiveness, the present invention asillustratively described and exemplified hereinabove, has the followingbeneficial and advantageous aspects, characteristics, or features.

The components (powdered diatomite matrix, nanometer sized zero valentmetal particles, at least one electron transfer mediator, and,optionally, vermiculite) of the zero valent metal composite of thepresent invention are natural, user-friendly, and environmentallyfriendly.

The powdered diatomite matrix is highly absorbent, physically andchemically stable, nearly indestructible, and ordinarily chemicallyinert to most common water contaminants.

The powdered diatomite matrix is highly absorbent, which in addition tothe catalytic activity of the nanometer sized zero valent metalparticles, provides an additional mechanism for decreasing theconcentration of contaminants in contaminated water, by absorbing andretaining the contaminants on or/and in the matrix.

The powdered diatomite matrix is highly permeable, and thereforepromotes (in-situ) funneling or channeling of contaminated water to atreatment zone, thus reducing both the amounts of material and theextent of the area needed for treatment and remediation of contaminatedwater.

Inclusion of the powdered diatomite matrix in the zero valent metalcomposite, wherein the zero valent metal particles are incorporated onor/and in (dispersed throughout, supported by, and adhering in achemical bonding manner to) the powdered diatomite matrix, drasticallyreduces the amount of zero valent metal that is required forcatalytically treating contaminated water, thus increasing the economicviability of treatment and remediation of contaminated water.

Incorporation of the nanometer sized zero valent metal particles doesnot significantly affect the small- and large-scale porosity of thepowdered diatomite matrix, such that pores of the diatomite matrixremain open to fluid flow.

The zero valent metal particles which are incorporated on or/and in thepowdered diatomite matrix have extremely large specific surface areas.This physicochemical characteristic of the zero valent metal particlesis directly related to, and used for exploiting, chemical reductionreaction activity by the zero valent metal composite. Moreover, thelarge specific surface areas of the nano-sized zero valent metalparticles significantly reduces the effects of catalyst fouling andextends the activity period of the zero valent metal included in thezero valent metal composite.

The configuration of the zero valent metal composite having nanometersized zero valent metal particles being incorporated on or/and in thepowdered diatomite matrix decreases the rate of oxidation of theordinarily pyrophoric nano-sized metal particles, thus enabling easierhandling, transportation, use, and application, of the zero valent metalcomposite.

The components (powdered diatomite matrix, nanometer sized zero valentmetal particles, at least one electron transfer mediator, and,optionally, vermiculite) of the zero valent metal composite, singly, orin a synergistic combination, catalytically decrease contaminantconcentrations in contaminated water. For example, an electron transfermediator, which is incorporated on or/and in the powdered diatomitematrix of the zero valent metal composite, and which may also chemicallyadhere to the metallic surface of the zero valent metal particles, andfor the specific embodiment of the zero valent metal compositeadditionally including vermiculite, may also chemically or/andphysically adhere to the hydrated silicate surface of the vermiculite,primarily functions as a chemical substance which is catalyticallyactive. Thus, the electron transfer mediator, along with thecatalytically active nanometer sized zero valent metal particles, cansynergistically function in combination for enhancing the catalyticreactions taking place during the catalytic treatment of thecontaminated water.

For the alternative preferred embodiment of the zero valent metalcomposite, additionally including vermiculite, the vermiculite primarilyfunctions as a physical scaffold, being a frame or platform, forphysically supporting the powdered diatomite matrix on or/and in whichare incorporated the zero valent metal particles and the at least oneelectron mediator. The vermiculite may also function by increasing theadsorption, in addition to the porosity and permeability (permeability,k), properties, parameters, characteristics, and behavior, of the zerovalent metal composite. The vermiculite may also function as achemically active species, for example, by serving as an additionalsupport for chemisorption of reaction species, participating in theredox (reduction-oxidation) reaction(s) taking place betweencontaminants in contaminated water and the zero valent metal compositeof the present invention, during the catalytic treatment of thecontaminated water.

Another advantageous feature of the additional inclusion of thevermiculite, is that in the alternative preferred embodiment of themanufacturing method, during the reaction taking place for forming thezero valent metal composite (including vermiculite), in addition to theelectron transfer mediator, the vermiculite may also function as achemically active species, for example, by actively facilitating(mediating, catalyzing, or co-catalyzing) the reduction of the oxidizedform of the metal in the metal salt to the zero valent metal, or/and byactively facilitating (mediating, catalyzing, or co-catalyzing) thebonding of the zero valent metal to the silica surface of the powdereddiatomite matrix.

The present invention, as illustratively described and exemplifiedhereinabove, is generally applicable to a variety of industries, whichhave a need for (in-situ or ex-situ) treating any of a wide variety ofdifferent forms of contaminated water, for example, sub-surface water,surface water, above-surface water, water vapor, gaseous water, or anycombination thereof, which are contaminated with any number of a widevariety of different types or kinds of organic or/and inorganic chemicalcontaminants.

The present invention is particularly applicable to treating such formsof contaminated water wherein the water contaminants are organicspecies, for example, halogenated organic compounds and halogencontaining degradation products thereof; inorganic species, for example,metal elements, metal element containing inorganic species, nonmetalelements, and nonmetal element containing inorganic species; or anycombination thereof.

The present invention is particularly applicable for treatingcontaminated water located in geographical areas or regions designatedby governmental environmental agencies as requiring waste remediation orclean-up, or/and contaminated water associated with commercial processesrequiring environmental control, monitoring, and treatment, of effluentcontaminated water.

As previously stated hereinabove, although the present invention isprimarily focused on applications involving catalytic treatment ofcontaminated water, wherein the contaminated water is, for example, aform of sub-surface water, surface water, above-surface water, watervapor, gaseous water, or any combination thereof, it is to be fullyunderstood that the present invention is also applicable to (in-situ orex-situ) catalytically treating contaminated non-aqueous fluids (inliquid, vapor, or/and gaseous forms), for decreasing contaminantconcentrations therefrom.

It is appreciated that certain aspects and characteristics of theinvention, which are, for clarity, described in the context of separateembodiments, may also be provided in combination in a single embodiment.Conversely, various aspects and characteristics of the invention, whichare, for brevity, described in the context of a single embodiment, mayalso be provided separately or in any suitable sub-combination.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the present invention.

While the invention has been described in conjunction with specificembodiments and examples thereof, it is evident that many alternatives,modifications and variations will be apparent to those skilled in theart. Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

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1. A zero valent metal composite comprising a powdered diatomite matrixon or/and in which is incorporated zero valent metal particles having asize in a range of between about 1 nm and about 1000 nm and at least oneelectron transfer mediator, wherein concentration of said zero valentmetal particles is in a range of between about 0.1 weight percent andabout 20 weight percent of total weight of the composite, and whereinsaid at least one electron transfer mediator comprises at least oneporphyrinogenic organometallic complex.
 2. The composite of claim 1,wherein said powdered diatomite matrix has a particle size in a range ofbetween about 1 micron and about 150 microns.
 3. The composite of claim1, wherein said metal in said zero valent metal particles comprises atleast one transition metal.
 4. The composite of claim 1, wherein saidzero valent metal particles have a size in a range of between about 5 nmand about 500 nm.
 5. The composite of claim 1, wherein concentration ofsaid at least one electron transfer mediator is in a range of betweenabout 0.001 weight percent and about 1 weight percent of total weight ofthe composite.
 6. The composite of claim 1, additionally includingvermiculite.
 7. The composite of claim 6, wherein said vermiculite has apiece size in a range of between about 0.01 mm and about 20 mm.
 8. Thecomposite of claim 6, wherein concentration of said vermiculite is in arange of between about 20 weight percent and about 95 weight percent oftotal weight of the composite.
 9. A zero valent metal compositecomprising a composition consisting essentially of a powdered diatomitematrix on or/and in which is incorporated zero valent metal particleshaving a size in a range of between about 1 nm and about 1000 nm and atleast one electron transfer mediator, wherein concentration of said zerovalent metal particles is in a range of between about 0.1 weight percentand about 20 weight percent of total weight of the composite, andwherein said at least one electron transfer mediator comprises at leastone porphyrinogenic organometallic complex.
 10. The composite of claim9, wherein said powdered diatomite matrix has a particle size in a rangeof between about 1 micron and about 150 microns.
 11. The composite ofclaim 9, wherein said metal in said zero valent metal particlescomprises at least one transition metal.
 12. The composite of claim 9,wherein said zero valent metal particles have a size in a range ofbetween about 5 nm and about 500 nm.
 13. The composite of claim 9,wherein concentration of said at least one electron transfer mediator isin a range of between about 0.001 weight percent and about 1 weightpercent of total weight of the composite.
 14. A method of manufacturinga zero valent metal composite, the method comprising incorporating zerovalent metal particles having a size in a range of between about 1 nmand about 1000 nm and at least one electron transfer mediator on or/andin a powdered diatomite matrix, wherein concentration of said zerovalent metal particles is in a range of between about 0.1 weight percentand about 20 weight percent of total weight of the composite, andwherein said at least one electron transfer mediator comprises at leastone porphyrinogenic organometallic complex.
 15. The method of claim 14,wherein said powdered diatomite matrix has a particle size in a range ofbetween about 1 micron and about 150 microns.
 16. The method of claim14, wherein said metal in said zero valent metal particles comprises atleast one transition metal.
 17. The method of claim 14, wherein saidzero valent metal particles have a size in a range of between about 5 nmand about 500 nm.
 18. The method of claim 14, wherein concentration ofsaid at least one electron transfer mediator is in a range of betweenabout 0.001 weight percent and about 1 weight percent of total weight ofthe composite.
 19. The method of claim 14, further comprising, prior to,during or subsequent to said incorporating, adding vermiculite, suchthat the zero valent metal composite additionally includes saidvermiculate.
 20. The method of claim 19, wherein said vermiculite has apiece size in a range of between about 0.01 mm and about 20 mm.
 21. Themethod of claim 19, wherein concentration of said vermiculite is in arange of between about 20 weight percent and about 95 weight percent oftotal weight of the composite.
 22. The method of claim 14, wherein saidincorporating comprises: providing an aqueous solution of a metal saltand said at least one electron transfer mediator; adding said powdereddiatomite matrix to said aqueous solution, to thereby form an aqueousslurry of said metal salt, said at least one electron transfer mediator,and said powdered diatomite matrix; and contacting said aqueous slurrywith a reducing agent, to thereby produce said zero valent metalparticles, and further to thereby incorporate said zero valent metalparticles and said at least one electron transfer mediator on or/and insaid powdered diatomite matrix.
 23. The method of claim 22, wherein saidmetal salt comprises at least one transition metal salt.
 24. The methodof claim 22, wherein said at least one electron transfer mediatorcomprises at least one porphyrinogenic organometallic complex.
 25. Themethod of claim 22, wherein said incorporating further comprises addingvermiculite to said aqueous solution, to thereby form a mixture of saidvermiculite and said aqueous solution, such that said adding saidpowdered diatomite matrix is to said mixture, and said aqueous slurry isof said metal salt, said at least one electron transfer mediator, saidpowdered diatomite matrix and said vermiculite.
 26. A method forcatalytically treating contaminated water, the method comprisingexposing the contaminated water to a catalytically effective amount of azero valent metal composite comprised of a powdered diatomite matrix onor/and in which is incorporated zero valent metal particles having asize in a range of between about 1 nm and about 1000 nm and at least oneelectron transfer mediator, to thereby decrease concentration of atleast one contaminant in the contaminated water, said at least onecontaminant comprising a halogenated organic compound, whereinconcentration of said zero valent metal particles is in a range ofbetween about 0.1 weight percent and about 20 weight percent of totalweight of said composite, and wherein said at least one electrontransfer mediator comprises at least one porphyrinogenic organometalliccomplex.
 27. The method of claim 26, wherein said powdered diatomitematrix has a particle size in a range of between about 1 micron andabout 150 microns.
 28. The method of claim 26, wherein said metal insaid zero valent metal particles comprises at least one transitionmetal.
 29. The method of claim 26, wherein said zero valent metalparticles have a size in a range of between about 5 nm and about 500 nm.30. The method of claim 26, wherein concentration of said at least oneelectron transfer mediator is in a range of between about 0.001 weightpercent and about 1 weight percent of total weight of the composite. 31.The method of claim 26, wherein said zero valent metal compositeadditionally includes vermiculite.
 32. The method of claim 31, whereinsaid vermiculite has a piece size in a range of between about 0.01 mmand about 20 mm.
 33. The method of claim 31, wherein concentration ofsaid vermiculite is in a range of between about 20 weight percent andabout 95 weight percent of total weight of the composite.
 34. The methodof claim 26, wherein said exposing is performed by using a system whichincludes said zero valent metal composite and at least one unit forcontaining said catalytically effective amount of said zero valent metalcomposite.
 35. A zero valent metal composite comprising a powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having a size in a range of between about 1 nm and about 1000nm, at least one electron transfer mediator, and vermiculite, whereinconcentration of said vermiculite is in a range of between about 20weight percent and about 95 weight percent of total weight of thecomposite.
 36. The composite of claim 35, wherein said powdereddiatomite matrix has a particle size in a range of between about 1micron and about 150 microns.
 37. The composite of claim 35, whereinsaid metal in said zero valent metal particles comprises at least onetransition metal.
 38. The composite of claim 35, wherein said zerovalent metal particles have a size in a range of between about 5 nm andabout 500 nm.
 39. The composite of claim 35, wherein concentration ofsaid zero valent metal particles is in a range of between about 0.1weight percent and about 20 weight percent of total weight of thecomposite.
 40. The composite of claim 35, wherein said at least oneelectron transfer mediator comprises at least one porphyrinogenicorganometallic complex.
 41. The composite of claim 35, whereinconcentration of said at least one electron transfer mediator is in arange of between about 0.001 weight percent and about 1 weight percentof total weight of the composite.
 42. The composite of claim 35, whereinsaid vermiculite has a piece size in a range of between about 0.01 mmand about 20 mm.
 43. A method of manufacturing a zero valent metalcomposite, the method comprising incorporating zero valent metalparticles having a size in a range of between about 1 nm and about 1000nm, and at least one electron transfer mediator on or/and in a powdereddiatomite matrix, the method further comprising, prior to, during orsubsequent to said incorporating, adding vermiculite, such that the zerovalent metal composite additionally includes said vermiculate, whereinconcentration of said vermiculite is in a range of between about 20weight percent and about 95 weight percent of total weight of thecomposite.
 44. The method of claim 43, wherein said incorporatingcomprises: providing an aqueous solution of a metal salt, said at leastone electron transfer mediator and said vemiculite; adding said powdereddiatomite matrix to said aqueous solution, to thereby form an aqueousslurry of said metal salt, said at least one electron transfer mediator,said vermiculite and said powdered diatomite matrix; and contacting saidaqueous slurry with a reducing agent, to thereby produce said zerovalent metal particles, and further to thereby incorporate said zerovalent metal particles, said at least one electron transfer mediator andsaid vermiculite on or/and in said powdered diatomite matrix.
 45. Amethod for catalytically treating contaminated water, the methodcomprising exposing the contaminated water to a catalytically effectiveamount of a zero valent metal composite comprised of a powdereddiatomite matrix on or/and in which is incorporated zero valent metalparticles having a size in a range of between about 1 nm and about 1000nm, at least one electron transfer mediator and vermiculite, to therebydecrease concentration of at least one contaminant in the contaminatedwater, wherein concentration of said vermiculite is in a range ofbetween about 20 weight percent and about 95 weight percent of totalweight of the composite.
 46. The method of claim 45, wherein saidexposing is performed by using a system which includes said zero valentmetal composite and at least one unit for containing said catalyticallyeffective amount of said zero valent metal composite.